MP2617A, MP2617B Datasheet by Monolithic Power Systems Inc.

The Future of Analog lc Technology

MP2617A, MP2617B

3A Switching Charger with NVDC

Power Path Management

For Single Cell Li+ Battery

MP2617A, MP2617B Rev. 1.23 www.MonolithicPower.com 1

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DESCRIPTION

The MP2617A / MP2617B is a monolithic

switch mode battery charger with power path

management for single-cell Li-ion batteries in a

wide range of tablet and other portable devices.

It integrates a synchronous BUCK regulator to

provide regulated voltage for powering the

system output and at the same time charging

the battery. This device supports both USB and

high power DC adapter input. In USB mode, the

input current limit can be programmed to

450mA or 825mA via the logic pins to cover the

USB2.0 and USB3.0 specifications. When the

adapter input is present, the input current can

also be limited in order to avoid overloading of

the DC adapter. Input current limit can be

programmed up to 3A.

The smart power path management allows

MP2617A and MP2617B to regulate the system

voltage for powering an external load and

charging the battery independently and

simultaneously. This allows immediate system

operation even under missing or deeply

discharged battery. When the input current limit

is reached, the system load is satisfied in

priority, then the charger will take the remaining

current to charge the battery. Additionally, the

smart power path control allows an internal

connection from battery to the system in order

to supplement additional power to the load in

the event the system power demand increases

over the input limited power or the input is

removed.

The MP2617A / MP2617B features high

integration with all the power switches integrate

inside. No external MOSFET, blocking diodes,

or current sense resistor is required.

Two status monitor output pins are provided to

indicate the battery charge status and power

source status. Other features include trickle

charge, battery temperature monitoring, timer

and thermal limiting regulation on chip.

The MP2617A / MP2617B is available in QFN

3mmx4mm package.

FEATURES

 4V to 10V Operating Input Voltage

 Smart Power Path Management

 Five Control Loops: Input Current Limit,

Input Voltage Limit, Constant Charge

Current, Terminal Battery Control and

Thermal Fold-Back.

 1.6MHz Switching Frequency

 Programmable Input Current Limit

 Programmable Charge Current

 Single Input for USB and AC adapter

 Cover USB2.0 and USB3.0 Input

Specification

 Fully Integrated Power Switches

 No External Blocking Diode and Sense

Resistor Required

 Charging Operation Indicator

 Built-in Programmable Charging Timer

 Thermal Limiting Regulation on Chip

 Battery Temperature Monitor

 Tiny Package Features Small Size.

APPLICATIONS

 Smart Phone

 E-Book

 GPS

 Portable Media Player

 Portable Hand-held Solution

 Tablet PC

All MPS parts are lead-free, halogen free, and adhere to the RoHS

directive. For MPS green status, please visit MPS website under Quality

Assurance.

“MPS” and “The Future of Analog IC Technology” are Registered

Trademarks of Monolithic Power Systems, Inc.

II'IIE' EFFICIENCY ("/a) -\|—H—¢ Efﬂclency vs. System Current Charger disabled. vsvs=4.sv v ﬂ 7 v. =5v \\ 3 N 0.5 115 22.5 33.5 I595 (A) EFFICIENCV ("M Efficiency vs. System Current Charger disabled, sts=‘-3V ma ‘ VIN-5V 70 so so 40 0 1 2 3 lsvs (A)

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

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TYPICAL APPLICATION

L

CHGOK

ACOK

NTC

EN

AGND

TMR

BATT

BST

SW

OFF

ON

C3

M1

AC adapter

/USB input IN

M0

VCC

VILIM

SYS

ISET RISET

CSYS

CBATT

SYS Load

RNTC

C2

MP2617A/B

RILIM

SYSFB

ILIM

R1

R2

R3

R4

CIN

0

PGND

vBATT

ICHG

RT1

RT2 CTMR

C1

MP2617A

MP2617B

MP2617 Family Table

Features

MP2617A

MP2617B

Battery Charge Full Voltage

4.35V

4.2V

I'IIIE'

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

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ORDERING INFORMATION

Part Number

Package

Top Marking

MP2617AGL*

QFN-20 (3mmx4mm)

MP2617A

MP2617BGL

QFN-20 (3mmx4mm)

MP2617B

* For Tape & Reel, add suffix –Z (e.g. MP2617AGL–Z);

PACKAGE REFERENCE

TOP VIEW

1

2

3

4

5

6

7 8 9 10

11

12

13

14

15

16

17181920

BST

SW

IN

SW

PGND

EN

M0

M1

CHGOK

ACOK

AGND

SYSFB

SYS

BATT

ISET

NTC

VCC

VLIM

TMR

ILIM

I'IIIE'

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

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PIN FUNCTIONS

Package

Pin #

Name

Description

1

BST

Bootstrap. A capacitor is connected between SW and BST pin to form a floating supply

across the power switch driver to drive the power switch’s gate above the supply voltage.

3

IN

Power input of the IC from adapter or USB.

2,4

SW

Switch output.

5

PGND

Power ground.

6

EN

_____

Function logic control pin of the IC. Logic low to enable the part and logic high to disable the

part.

7

M0

Mode Select Input Pin, in combination with M1 pin, setting the input current limit mode.

8

M1

Mode Select Input Pin, in combination with M0 pin, setting the input current limit mode.

9

CHGOK

_____________

Open drain output. It is pulled low during charging. And it is pulled high through an external

resistor to VCC to indicate charge completed.

10

ACOK

__________

Open drain output. It is pulled low to indicate the presence of a valid input power supply.

Otherwise, it is pulled high through an external resistor to VCC to indicate invalid input or

removed input.

11

AGND

Analog ground.

12

SYSFB

SYS voltage program pin. Connect a resistor divider from the pin to SYS and AGND to

program the system output voltage. Leave the pin float to disable the function.

13

SYS

DC-DC regulator output to power the system load and charge the battery.

14

BATT

Positive battery terminal.

15

ISET

Charge current program pin. A resistor from the pin to AGND can program the charge

current during CC charge. Float the pin will disable the charge function.

16

NTC

Thermistor input. Connect a resistor from this pin to VCC and the thermistor from this pin to

ground. The thermistor is usually inside the battery pack.

17

ILIM

Input current limit program pin. A resistor from the pin to AGND can program the input

current limit with adapter input.

18

TMR

Set timer out period. Connect TMR pin to AGND to disable the internal timer.

19

VLIM

Input voltage clamp program pin.

20

VCC

Supply voltage of the IC.

I'I'IIE' he me he anenl

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

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ABSOLUTE MAXIMUM RATINGS (1)

IN, SW ........................................ -0.3V to +20V

BATT, SYS .................................... -0.3V to +6V

BST ............................................. -0.3V to +26V

All Other Pins ................................. -0.3V to +6V

Continuous Power Dissipation (TA = +25°C) (2)

QFN20 3mmx4mm .................................... 2.6W

Junction Temperature .............................. 150C

Lead Temperature ................................... 260C

Storage Temperature.................–65°C to 150°C

Recommended Operating Conditions (3)

Supply Voltage VIN .......................... 4.0V to 10V

Operating Junction Temp. (TJ) .... -40°C to +125°C

Thermal Resistance (4) θJA θJC

QFN-20 (3mmx4mm) ............. 48 ...... 11 ... C/W

Notes:

1) Exceeding these ratings may damage the device.

2) The maximum allowable power dissipation is a function of the

maximum junction temperature TJ (MAX), the junction-to-

ambient thermal resistance θJA, and the ambient temperature

TA. The maximum allowable continuous power dissipation at

any ambient temperature is calculated by PD (MAX) = (TJ

(MAX)-TA)/θJA. Exceeding the maximum allowable power

dissipation will cause excessive die temperature, and the

regulator will go into thermal shutdown. Internal thermal

shutdown circuitry protects the device from permanent

damage.

3) The device is not guaranteed to function outside of its

operating conditions.

4) Measured on JESD51-7, 4-layer PCB.

I'IIIE' H Dstom LDSIONY VVUM sts REF

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

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ELECTRICAL CHARACTERISTICS

VIN = 5.0V, TA = 25C, unless otherwise noted.

Parameters

Symbol

Condition

Min

Typ

Max

Units

Input Power (IN)

IN Operating Range

VIN

4.0

10

V

IN Under Voltage Lockout

Threshold

Rising

3.65

3.8

3.95

V

Falling

3.35

3.5

3.65

V

IN vs. BATT Threshold

Rising

240

280

320

mV

Falling

40

70

120

mV

BST Voltage Threshold

VBST-VSW

Rising

2.55

2.9

3.25

V

Hysteresis

150

mV

Switching Frequency

1.4

1.6

1.8

MHz

Input Current Limit

IIN

USB2.0 Mode

400

450

500

mA

USB3.0 Mode

750

825

900

mA

Default Mode

1840

2000

2160

mA

Programmable Mode, RILIM=23k

(MP2617B)

1840

2000

2160

mA

Programmable Mode, RILIM=22.47k

(MP2617A)

1840

2000

2160

mA

Programmable Mode,

RILIM=48k (MP2617A)

900

950

1000

mA

Input Current Limit Reference

Voltage

VILIM

1.1

1.14

1.18

V

High-side NMOS On Resistance

RH_DS(ON)

Include the BLOCK FET

120

130

mΩ

Low-side NMOS On Resistance

RL_DS(ON)

80

100

mΩ

High-side NMOS Peak Current

limit

3.8

4.8

5.8

A

Input Voltage Clamp Threshold

VVLIM

Voltage on VLIM

1.49

1.52

1.55

V

Input Quiescent Current

IIN

Charger Enabled, USB2.0 Mode

2.4

5

mA

Charger Enabled, USB3.0 Mode

2.8

5

mA

Charger Enable, Programmable Mode

3.8

5

mA

Charger Enabled, Default Mode

3.8

5

mA

Disabled, EN=0V

3

5

uA

SYS to IN reverse current

blocking

SYS=SW=4.5V,VIN=0V, monitor VIN

leakage

0.01

0.2

uA

SYS Output (MP2617A)

Minimum SYS Regulation

Voltage

VSYS

SYS voltage @ VBATT≤3.4V, SYSFB

float

3.45

3.6

3.75

V

SYS Regulation Voltage

VSYS

3.4V<VBATT≤4.2V, SYSFB float

BATT Float

3.5

VBATT+

0.2V

4.63

V

User Programmed by SYSFB

4.22

4.63

V

SYS Reference Voltage

VSYS_REF

1.135

1.152

1.170

V

I'IIIE' sts REF VIN lsvs VSVS>VBATT lmxcng la;

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

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ELECTRICAL CHARACTERISTICS (continued)

VIN = 5.0V, TA = 25C, unless otherwise noted.

Parameters

Symbol

Condition

Min

Typ

Max

Units

SYS Output (MP2617B)

Minimum SYS Regulation Voltage

VSYS

SYS voltage @ VBATT≤3.4V,

SYSFB float

3.45

3.6

3.75

V

SYS Regulation Voltage

VSYS

3.4V<VBATT≤4.2V, SYSFB float

BATT Float

3.5

VBATT+

0.2V

4.5

V

User Programmed by SYSFB

4.08

4.4

V

SYS Reference Voltage

VSYS_REF

1.135

1.152

1.170

V

Battery Discharge

BATT to SYS Resistance

VIN=0V, ISYS=200mA, VBATT=4.2V

40

50

mΩ

BATT to SYS Current Limit

VSYS>VBATT–800mV, VBATT=4.2V

4

5

6

A

SYS short

230

mA

Battery Charger Voltage Spec (MP2617A)

Terminal Battery Voltage

VBATT

VBATT>VRECH, ICHG≤IBF, SYSFB float

4.328

4.35

4.372

V

VSYS<4.2V Programmed by

SYSFB Pin

VSYS-

0.04 x

IBF

V

Recharge Threshold at VBATT

VRECH

SYSFB Float

4.04

4.14

4.24

V

SYSFB programmed

3.99

4.09

4.19

V

Recharge Hysteresis

85

mV

Trickle Charge Threshold

3.01

3.11

3.21

V

Trickle Charger Hysteresis

200

mV

Battery Charger Voltage Spec (MP2617B)

Terminal Battery Voltage

VBATT

VBATT>VRECH, ICHG≤IBF, SYSFB float

4.179

4.2

4.221

V

VSYS<4.2V Programmed by

SYSFB Pin

VSYS-

0.04 x

IBF

V

Recharge Threshold at VBATT

VRECH

SYSFB Float

3.9

4.0

4.1

V

SYSFB programmed

3.85

3.95

4.05

V

Recharge Hysteresis

85

mV

Trickle Charge Threshold

2.9

3

3.1

V

Trickle Charger Hysteresis

200

mV

Battery Charger Current Spec

Trickle Charge Current

ITRICKLE

10%

ICC

Termination Charger Current

IBF

5%

10%

15%

ICC

IBF Maximum Limit

150

200

mA

Constant Current Mode Charge

Current

ICC

RISET=760

2.475

2.75

3.02

5

A

RISET=1.53k

1.26

1.4

1.54

A

RISET=4.6k

0.405

0.450

0.495

A

I'IIIE'

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

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ELECTRICAL CHARACTERISTICS (continued)

VIN = 5.0V, TA = 25C, unless otherwise noted.

Parameters

Symbol

Condition

Min

Typ

Max

Units

ISET Reference Voltage

1.1

1.15

1.2

V

Battery UVLO

Rising

2.4

2.6

2.8

V

Falling

2.2

2.4

2.6

V

Idea Diode Regulation Voltage

VSYS

Supplement Mode

VBATT-

65mV

mV

BATT Leakage Current

IBATT

VBATT=4.2V, SYS float,

VIN=PGND

20

30

µA

ACOK

__________, CHGOK

_____________

ACOK

__________, CHGOK

_____________ Pin Output

Low Voltage

Sinking 5mA

270

350

mV

ACOK

__________,CHGOK

_____________Pin Leakage

Current

Connected to 3.3V

0.1

0.5

μA

Timer

Trickle Charge Time

CTMR=0.1µF, ICHG=1A

45

Min

Total Charge Time

CTMR=0.1µF, ICHG=1A

6.5

Hour

Negative Temperature Coefficient (NTC) Control

NTC Low Temp Rising

Threshold

VTHL

RNTC=NCP18XH103F 0°C

63

65

67

%VCC

Hysteresis on Low Temp

Threshold

35

mV

NTC High Temp Falling

Threshold

VTHH

RNTC=NCP18XH103F, 50°C

32

33.5

35

%VCC

Hysteresis on High Temp

Threshold

70

mV

VCC Supply

VCC UVLO

Rising

3.15

3.35

3.55

V

Falling

2.8

3

3.2

V

VCC Output Voltage

0mA<IVCC<25mA, VIN=6V

4.3

4.5

4.6

V

VCC Output Current Limit

40

mA

Logic

EN

Input Low Voltage

0.4

V

EN

Input High Voltage

1.5

V

EN

Input Current

EN

=4V

4

8

μA

EN

=0V

-0.5

-0.1

M0, M1

Logic High

1.5

V

Logic Low

0.4

V

I'IIIE'

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

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ELECTRICAL CHARACTERISTICS (continued)

VIN = 5.0V, TA = 25C, unless otherwise noted.

Parameters

Symbol

Condition

Min

Typ

Max

Units

Protection

Thermal Limit Temperature

120

°C

Thermal Shutdown

150

°C

I'IIIE' Charge Current vs. Battery Regulatlon vs. System Voltage Regulatlon Battery Voltage Temperature vs. Temperature 2.5 421 3.05 a 4.200 2 E 4.200 3'8 VBA .5v r E 4.204 315 A 1.5 o 4.20: SE 3 4.2 3.7 _ 1 3 4.100 2 4.190 3'65 0.5 E 2.1: 35 m . o 4.10 3.55 2 2.5 :1 3.5 4 4.5 o 25 50 75 100 125 .50 —25 n 25 50 75 100 125 VunIV) TEMPWTURECC) TEMPWTUREFC) usea.o Input Current US$241 Input Current Default Mode Input Current lelt vs. Temperature lelt vs. Temperature lelt vs. Temperature 1: I o. o o a 5 m a a 400 47B 460 LED MD ACID 420 410 400 1:: can o 0553.0 INPUT CURRENT LIMIT(mA) 3‘ a 1‘ a! 7.5 g E 2 g 2 3 usa2.n INPUT CURRENT LIMIT(mA 0 -5|] -25 U 25 50 75100125 DEFAULT MODE INPUT CURRENT L| M|T(mA) ; 3 G G E S E c: 01 o 01 0 ur a a o o o o o c -50 -25 o 25 50 15 100125 50 -25 0 25 50 75100125 TEMPERATUREI'C) TEMPERATURECC) TEMPERATURE('C) Program Mode Input Current Battery Auto-recharge Ideal Dlode Regulatlon vs. H ﬁmpﬁg. Temperature Threshold vs. Temperature Temperature .( = E N ' E3000 4.1 70 E E 68 2960 4.05 Z r E \_ 1 S‘ g 2920 .. 4.02 5 65 ~ 15 a: _ E % 2000 9 350 IE 64 i a 8 2840 3.94 62 s g 2500 3.9 so i -50 -25 0 25 50 75 100125 -50 -25 0 25 50 75 100125 50 -25 0 25 50 75100125 3 TEMPERATURE('C) TEMPERATURE('C) TEMPERATUREl'C)

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TYPICAL PERFORMANCE CHARACTERISTICS

VIN = 5.0V, VBATT = Full Range, Default Mode, IIN Limit=2A, VSYS=4.4V, R6 and R7 are float, ICHG=2A,

VIN Clamp=4.5V, L = 1.2 µH, TA = +25ºC, Test in MP2617B, unless otherwise noted.

I'I'IIE' Battery charge Curve Auto-Recharge USE IN Banery Charge Curve lsvs = M lsvs = 0A usazn Mode, Isys = 0A 1Vldiv. f Vnrr / — 1V/dw. . CHECK OHGOK W’gW-n -———————-—————-— 2w . mu” MKI . .—.—-———-.L . vmﬁ . Y 1V/dIV. , ' ' harm .. lean - wan. Wd'“ Zeldlv. 2mm. as/aw. USE IN Bakery charge Curve Tc Shady State TC Steady State usaan Mode, Isys = 0.5A van-F 2.6V, Isys = 0.5A usuao Mode,VaA‘-r= 2.6V lsvs = 05A ﬂ VBATI New.” VM" v N aw. , MHWWF VSWE w w w w u ' ZVIdw. , ‘ , V W4 Mﬂ/ WSW u u u u u u I \v/\ \/\/\/ Worn/dull. 5mm“; IE,m I ' zoom/div.P 3“"? 25m. «Inns/div. zoom/aw. mans/div. CC Steady State CC Steady Slate CC Steady State v3," = MN, Isys =1.5A @ Supplement Mode usaan Moaaym-r: 3.3V van-F 313v, lsvs = 3A kvs = W“ 1: ‘- VIATT VBATI VENT Ivan 3 Man. 1 zvmw. 3 V3 V V Him.” Wm F Mm” . _n1 ‘ ‘ mm»! - W I ’\/‘/\/ \/\/\/ TI | m; 1 «7? mamas-arr 1 1’4“ Wd'VL-ﬁ mummiLLT‘ 1mm” AWN/div. wens/aw. Inﬂux/div.

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

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TYPICAL PERFORMANCE CHARACTERISTICS (continued)

VIN = 5.0V, VBATT = Full Range, Default Mode, IIN Limit=2A, VSYS=4.4V, R6 and R7 are float, ICHG=2A,

VIN Clamp=4.5V, L = 1.2 µH, TA = +25ºC, Test in MP2617B, unless otherwise noted.

I'I'IIE' CV steady state CV steady State Battery Full Steady state vam = 42v, lsys = 0A VIN=9V- VsAn=4-ZV. |svs=1-5A Vam = 42% lsrs = 1-5“ W V VIATT 297:? I sz Wm. H Wm W SVIdIv. w W}??? D vs,” at , mm A A A 2013'? I g M’“ ”//‘/ A/M/r 13%vgmv V V V V ' "“ My N. IL IL II. soamIA/uw. u 1am. imam _ momma“ 1 «H smammw.L has/div. mans/div. «mus/div. Battery Float Steady State Input Current Lllnlt Input Current lelt No Battery. lsys - 1.5A vam - 3.7V, Ramp up Isys usa2.o ModeNmu-r- 3.7V Ramp UP lsvs mm /— NIL" sz v ' ' zwuw. 2y| (,5. h ’ «£115. V mu 2”SKEW Wm F tramwalv. I." hm I 1Nd~.@\ ‘WW- I aw. w 2}}; r \_ VBA'I'I If I IV/div. Zaldiv. Zaldiv. 25/div. Input Current lelt Input Voltage lelt System Current Translent usaan ModeNMrr = 3.7V 5VI1AAdapIer mysm = 42v Bamry Fu||.lsys = 14A transieanSNus RﬁmP “P lsvs Rim "P lsvs mm vm'ar / sts ”I,“ r mm It. ‘ . 'svs ZSIdiv. 1msldiv.

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

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TYPICAL PERFORMANCE CHARACTERISTICS (continued)

VIN = 5.0V, VBATT = Full Range, Default Mode, IIN Limit=2A, VSYS=4.4V, R6 and R7 are float, ICHG=2A,

L = 1.2 µH, TA = +25ºC, Test in MP2617B, unless otherwise noted.

I'I'IIE' Plug in Adapter Van" = .7v, laws = 2" Plug In Adapter No Emry. Vsys =42V. lsvs = 0.5A Remove Adapter Van-r = 3-7Vv lsvs = 2* 1msldiv. Plug In Adapter vw = 5VI1AAdaptar. Vm-r = 3.7V. lsys = 0.5A Plug in USB use 3.0 Mods, van-F 3.1V Isys = 2A swan. Vurr zymw. am wan. v WMN. I wan/L. ﬁns/div. En 0n vam- = 3.7V. lsys = 0A (vEm & sts has 2.5V (met) sts 5VYEN IVIdN. M' v wulv. 2%". IL ‘ an ‘ ‘ 2mm V's—*— v m aArr my law. v snow/aw. - 7 V st5 BA" u r svs IV/dlv. 1mm 5m“: male My...” m- Wars/div. zoms/div. 1 Ins/div. En Off En 0n Charge On Van-r = 3.7V. Isys = 0A vam- = 3.7V. Isvs =1.5A v. — 9v, Nu Banary, Isys = 3A (Vam- a. Vsys has 2.5V Onset) (van-r a. Vsys has 25v Oﬂsel) m, i v Vlszr swan. Maw VIN VIN 7 I" 201mm g/wuw. " ﬂ 5W" N am am =1 M ~ 500mV/dlv. snomwaw. , N sts 3 / mm. VSVS VSYS 5‘ VBAWB i ii mmVldiv. SDDIIIVIGN. ZVMN. IDA" ZNHN. I math“ ﬁns/div. 1msldiv. Ans/div.

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

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TYPICAL PERFORMANCE CHARACTERISTICS (continued)

VIN = 5.0V, VBATT = Full Range, Default Mode, IIN Limit=2A, VSYS=4.4V, R6 and R7 are float, ICHG=2A,

L = 1.2 µH, TA = +25ºC, Test in MP2617B, unless otherwise noted.

lI'IPS‘ Battery Insertion Battery Insertion Time Suspend @ NTC Fault van-F 3.7V. lays = 0A use 3.0 Mode. van-r: 3.7V. Isvs = DA err= 3.5V. Isys = 0A. cmﬁ = 150pF i i i ‘ WWW/”NA VMm \\\h 1VldN. VIN -"“ ‘ vIN 2v1uiv.n‘ Zvldlv. “‘ vii? P Vsys P _ _ Zvldiv. Van-r w mm m N. am . 1 ran. a 1:313“ ‘59}: m—._._.r 1331;” st/dlv. Anus/aw. wwdlv. 11mer Relreehed @ Battery Full Themal Shutdown Indleatlon @ Charge OnIOfl vam= 4.2V, um = 0A, cm = 150w st/div. lndlcatlon @ NTC Fault van-F 3.7V, Isys = 0A van-F 3.7V. lsys = 0A VaArr= 3.7V. Isvs = 0* Incmm ltle AmbiarTsmpemlure M Van Widiv. VIN ZVM' . ZﬂﬂmA/dlv. I 1mm Jams/div. lndlcatlon @ 11mer Out VBATI': WV. lsvs = M VSEY 1 5mm.” CHGOK 2mm. MOK ._.._J Mawf amid" Aﬂmsldiv. Indlcatlon @ Supplement an= 3.7V. lsys = 0A VIA" i ZVNW. /‘\/\ Vam vm mm m. 931,49 Wm". H Vmg‘ n — .- — — n1 WNW. Wldlv. r n 6x132 J‘“ r" r" 55,35” CHGOK ' ' mm. L J J L . - . W cm max“ 5 ""3; IVldlv. Wind/GM, l 11 1 w.” wuHF Zﬂﬂmsldlv. mops/aw. Aus/dlv.

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

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TYPICAL PERFORMANCE CHARACTERISTICS (continued)

VIN = 5.0V, VBATT = Full Range, Default Mode, IIN Limit=2A, VSYS=4.4V, R6 and R7 are float, ICHG=2A,

L = 1.2 µH, TA = +25ºC, Test in MP2617B, unless otherwise noted.

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OPERATION

Driver

IN

SW

C

L

HSG

LSG

BST

SYS

VBATx2

Charge

Pump

BATT

SYS

EA

SYSFB

SYSFB1

Max(A,B)

VBATT+200mV

EAO

Converter

control

40mO

BATTFB

VREF

ILIM

M1

M0

Trim

SYS

BATT

Ideal diode

regulation VTH

Battery switch

current limit

ISET

VIN

3.5 V coarse

LDO &

3.0 V UVLO

EN

VCC

4.5 V LDO

VBG

3.8V UVLO

VBG

VIN

UVLO

GND NTCTMRACOKCHGOK

EN

1.5V

EAO

VREF_CC

CC/ CV linear

charger

VLIM

3.6V

SYSFB1

SYSFB

BATTFB

Iref

Input current

limit reference

selector

Charger Control & Chip Logic

Bandgap

& Bias

EA

SYSFB

VBG

Figure 1—Function Block Diagram

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Introduction

The MP2617A and MP2617B is a switching

charger IC, with integrated smart power path

management for powering the system and

charging a single cell battery simultaneously and

independently.

The MP2617A and MP2617B includes input DC-

DC step down converter for wide range of DC

sources and USB inputs. It has precision average

input current limit to make maximum use of the

allowable input power. This feature allows fast

charging when powering from an USB port, and

ensures the input current never exceeds the

input power specification especially when the

input power comes from a USB port. Additionally,

the input current limit threshold can be

programmed by logic inputs or a resistor to

ground from the ILIM pin.

The MP2617A and MP2617B implements an on-

chip 40mΩ MOSFET which works as a full-

featured linear charger with trickle charge, high

accuracy constant current and constant voltage

charge, charge termination, auto recharge, NTC

monitor, built-in timer control, charge status

indication, and thermal protection. The charge

current can be programmed by an external

resistor connected from the ISET pin to AGND.

The IC limits the charge current when the die

temperature exceeds 120°C.

The 40mΩ MOSFET works as an ideal diode to

connecting the battery to the system load when

the input power is not enough to power the

system load. When the input is removed, the

40mΩ MOSFET is turned on allowing the battery

to power up the system.

With smart power path management, the system

load is satisfied in priority then the remaining

current is used to charge the battery. The

MP2617A and MP2617B will reduce charging

current or even use power from the battery to

satisfy the system load when its demand is over

the input power capacity.

Figure 1 shows the function block diagram of the

MP2617A and MP2617B.

DC-DC Step Down Converter

The DC-DC converter is a 1.6MHz step-down

switching regulator to provide the input power to

the SYS, which drives

the combination of the system load and battery

charger. The regulator contains input current

measurement and control scheme to ensure the

average input current remains below the level

programmed via ILIM pin or logic inputs M0&M1.

This meets the adapter capacity limit or stays in

compliance with USB specification.

When the input voltage is higher than UVLO and

280mV higher than the battery voltage, input

voltage OK signal is active (ACOK

—————— turns low) and

the DC-DC converter soft-starts. If the input

power is sufficient to supply the combination of

the system load and battery charger, and the

input current limit loop is not triggered. The

converter output voltage VSYS will be regulated:

1) If BATT>3.4V, VSYS is approximately 0.2V

above the battery voltage to minimize the power

loss of the battery charger during fast charging.

2) If BATT<3.4V, VSYS is fixed at 3.6V to power

the system immediately even when a drained

battery is inserted to be charged. Figure 2 shows

the relationship of VSYS vs. VBATT.

System voltage can also be regulated to any

value between 4.08V to 4.4V in MP2617B (4.22V

to 4.63V in MP2617A) by using a resistor divider

on the SYSFB pin. This is shown as R6 and R7

in Figure 10. If the SYSFB is left floating, the

system program is invalid, and VSYS is regulated

as Figure 2.

The converter adopts fixed off-time control to

extend the duty cycle (close to 100%) when the

input of the converter is close to VSYS.

4.4V

4.2V

3.6V

4.2V3.4V

200mV

VB A TT

VS Y S

Figure 2 — MP 2617B SYS Regulation

Output

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Close to 100% duty operation, BST refresh

operation makes sure the driver voltage of the

HS will be charged by turning on the LS until

negative IL hit a threshold. If the input power is

insufficient to supply the combination of the

system load and battery charger, the DC-DC

converter will limit the total power requirement by

restricting the input voltage, input current and the

peak current through the MOSFET. The power

path management will reduce the charge current

to satisfy the external system load in priority.

According to this feature, the USB specification is

always satisfied first. Even if the charge current is

set larger than the USB input current limit, the

real charge current will be reduced as needed.

Input Limit State

If the input power is insufficient to supply the

combination of the system load and battery

charger, the MP2617A and MP2617B

implements three input limit control loops to

reduce the charge current and satisfy the

external system load in priority. The input in this

case might be limited as follows: input current

limit, input voltage limit and DC-DC peak current

limit.

Input Current Limit: When the input current is

higher than the programmed input current limit

the input current limit loop takes the control of the

converter and regulates the input current at

constant value. When the battery voltage is over

3.4V, the output voltage (VSYS) will drop down

according to the increase of the system current,

and the charge current drops down after the

BATT-to-SYS switch (40mΩ MOSFET) is fully on

according to VSYS dropping down. During this

process, the system voltage is slightly higher

than VBATT. When the battery voltage is lower

than 3.4V, to maintain the minimum system

voltage and ensure the system operation, the

input current limit control will pull down the

charge current directly to reduce the load of the

converter so that the system current is satisfied

in priority.

Input Voltage Limit: A resistor divider from IN pin

to VLIM pin to AGND is used for the input voltage

limit control. When the voltage on VLIM pin hits

the reference voltage of 1.52V, the output of the

input voltage limit error amplifier will drop in

to control the operation duty. In this mode, the

input voltage will be clamped according to the

value set by the resistor divider. The control to

the system voltage and charge current is the

same as the one explained in the input current

limit. Charge current drops down to satisfy the

system current request first. This feature

provides a second protection to the input power

and ensures the safe operation of the input

adapter. Even if a wrong adapter is inserted, the

MP2617A and MP2617B can continue operation,

providing the maximum power to its load. User

can program the input voltage limit value through

the resistor divider from IN to VLIM to AGND.

Peak Current Limit: The peak current of the high

side switch of the DC-DC converter is sensed

during every cycle, it is compared to the

reference 4.8A. If the peak current hits the

threshold, the peak current limit mode is

triggered. The control of the charge current is the

same with the above two limits.

Input Current Limit Setting

The current at ILIM is a precise fraction of the

adapter input current. When a programming

resistor is connected from ILIM to AGND, the

voltage on ILIM represents the average input

current of the PWM converter. And the input

current approaches the programmed limit, ILIM

voltage reaches 1.14V.

The average input current limit can be set

through the resistor connecting from ILIM to

AGND according to the following expression:

IN_LIM

ILIM

40000

I =1.14 (mA)

R (kΩ)



When USB input, the input current limit is set

internally and the programmed value is invalid.

The MP2617A and MP2617B provides typical of

450mA input current limit for USB2.0

specification and a typical of 825mA for USB3.0

specification respectively.

The user can choose to set the input current limit

through the two logic pins M0 and M1 as shown

in Table 2 according to its input specification.

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When both M0 and M1 pins are float, they are

pulled to the logic high, under this condition, the

input current is limited to a default value of 2A.

Table 2―Input Current Limit Setting

M0

M1

Mode

Low

USB2.0 Mode

Low

High

USB3.0 Mode

High

Low

Programmable Mode

High/Float

Default Mode

Input Voltage Limit Setting

The input voltage can be limited at a value set by

a resistor divider from IN pin to VLIM pin to

AGND according to the following expression

(Typical Application Circuit):

IN_LIM

R1+R2

V =1.52 (V)

R2



When the voltage on VLIM pin drops and hits the

reference voltage 1.52V, the input voltage will be

clamped to the setting value.

Battery Charger

The MP2617A and MP2617B completes charge

operation consist of trickle charge, automatic

charge termination, charge status indication,

timer control, NTC indication, automatic recharge,

and thermal limiting.

When the PWM converter is out of soft start, the

battery charge cycle begins, the MP2617A and

MP2617B first determines if the battery is deeply

discharged. If the battery voltage is lower than

the trick charge threshold (typical 3.0V), the

battery charger starts in “trickle charge mode”.

The trickle charge current is limited to 10% of the

programmed charge current until the battery

voltage reaches 3.0V. If the charge stays in the

“trickle charging mode” for longer than ”trickle

charge timer period”, the “timer out” condition is

triggered, the charge is terminated and CHGOK

_____________

will start blinking to indicate that the battery is

unresponsive. When the battery voltage is above

3.0V, the charger is operating at “constant

current mode.” The current delivered to the

battery will try to reach the value programmed by

the ISET pin. Depending on the available input

power and system load conditions, the battery

charger may or may not be able to charge at the

full programmed rate. The system load is always

satisfied first over the battery charge current. If

the system load requirement is low, the battery

can be charged at full constant current.

When the battery voltage reaches the battery full

threshold, the charger enters the “constant

voltage mode” operation.

End of Charge (EOC) and Indication

In constant voltage charge mode, the battery

voltage is regulated at 4.2V (MP2617B) and

4.35V (MP2617A) (when SYSFB is float or SYS

is programmed higher than battery full threshold)

and the charge current decreases naturally.

Once the charge current hits the battery full

threshold IBF (1/10 programmed charge current),

the battery is fully charged and charge cycle is

terminated.

If the charge current drops below IBF because of

any limit condition, the MP2617A and MP2617B

will come out of CV mode, and the charge full

detection is invalid.

A safe timer starts at the beginning of each new

charge cycle and it monitors if the whole charge

period is within the programmed time limit. After

each charge cycle, when the battery is indicated

as full, the timer counter will be reset. If the time

is expired while the charging is still on going, the

timer will force the MP2617A and MP2617B to

terminate charging CHGOK

_____________ is blinking to indicate

the fault condition.

If system voltage is programmed lower than 4.2V

(MP2617B) and 4.35V (MP2617A) by the resistor

divider at the SYSFB pin, the battery will be

charged most close to VSYS until the charge

current reaches the IBF threshold.

Automatic Recharge

Once the battery charge cycle is completed, the

MP2617A and MP2617B turns off indicating the

battery full status. During this process, the

battery power may be consumed by the system

load or self discharge. If the input power is

always on, to ensure the battery not to be

exhausted, the new charge cycle will

automatically begin when the battery voltage falls

below the auto-recharge threshold VRCHG when

the SYSFB is float, and 50mV lower if the SYSFB

is connected to a resistor divider. The timer will

re-start when the auto-recharge cycle begins.

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During the charge off state when the battery is

fully charged, if the input power is recycled, or

the EN signal is refreshed, the charge cycle will

re-start and the timer will refresh even if the

battery voltage is above the auto-recharge

threshold.

Charge Current Setting

The charge current of the MP2617A and

MP2617B is programmed using a single resistor

from ISET pin to ground. The program resistor

and charge current are calculated using the

following equations:

CHG

SET

1800

I 1.15 (mA)

R (k )

 

At either constant current mode or constant

voltage mode, the voltage at the ISET pin is

proportional to the actual charge current

delivered to the battery, IBATT. The charge current

can be calculated by monitoring the ISET pin

voltage with the following formula:

CHG

ISET

BATT I×

1.15

V

=I

Additionally, the actual battery charge current

may be lower than the programmed current due

to limited input power available and prioritization

of the system load.

Battery charge full current threshold IBF is set

internally at 10% of the programmed charge

current. However, IBF has a 150mA maximum

limit which can not be exceeded.

Ideal Diode Mode

If the system current requirement increases over

the preset limit of the PWM converter, the

additional current will be drawn from the battery

via the BATT-to-SYS switch. To avoid very large

currents being drawn from the battery which

might affect the reliability of the device, the

MP2625B controls the charge switch to work at

the ideal diode mode regulating VSYS to VBATT-

65mV when VSYS is 40mV lower than VBATT is

detected. Only when VSYS is 40mV higher than

VBATT, the charger switch exits the ideal diode

mode, and the charge cycle softly restarts.

VBATT+40mV

Enable Ideal Diode Mode

VSYS

Disable Ideal Diode Mode

VBATT-40mV

Figure 3— Ideal Diode Mode Enable/Disable

Logic Control

The MP2617A and MP2617B have two separate

enable control pins.

EN

_____ is a logic control pin that controls the

operation of the whole IC. When EN

_____ is low, the

IC is enabled and the PWM converter output

powers the system and the charger. When EN

_____ is

high, both the PWM converter and the charger

are disabled. The BATT to SYS switch turns fully

on to connect the battery to power the system.

The ISET pin can be also used to control the

operation of the charger. Setting ISET pin floating

will disable the charger function while the output

of PWM converter will continue supply power to

system. On the other hand, a resistor from ISET

to AGND will enable the charging at the

programmed charge current.

The logic control of the ISET pin of the MP2617A

and MP2617B can be realized as Figure 4. In this

way, the user can choose logic low to be “off”

signal or logic high to be ”on” signal with a N-

MOSFET.

ISET

RISET

OFF ON

Figure 4— ISET Logic Control

Input Power Status Indication (ACOK

__________)

An internal under voltage lockout circuit monitors

the input voltage and keeps the IC in off state

until the input rises over the rising threshold

(3.8V). When the input voltage decreases below

threshold (3.5V), the IC will turn off, and the

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system load will be powered by the battery

automatically. ACOK

__________ is an open-drain, active-low

output that indicates the status of input power.

The input is considered valid when the input

voltage is over the UVLO rising threshold, and

310mV higher than the battery voltage to ensure

both the converter and the charger can operate

normally. If the input voltage from an adapter or

from a USB port is indicated OK, ACOK

__________ will turn

low.

During EN

_____ off or thermal shutdown conditions,

the ACOK

__________ turns high to indicate no power is

provided by the input to the system. The ACOK

__________

signal indicates if input supplies power to the

system load or not. Any other condition can not

affect the ACOK

__________ indication as long as the input

power is present.

Charge Status Indication (CHGOK

_____________)

CHGOK

_____________ is an open-drain, active-low output that

indicates the status of charge. CHGOK

_____________ will be

low during normal charging operation, turn high

after charge full, and blink if a fault condition

happens including NTC fault (battery temperature

invalid) and timer out (bad battery).

In the event of a fault condition, CHGOK

_____________

switches at 6Hz with the 50% duty cycle and

enter “blinking” mode. The user should check the

application circuit to find out the root cause of the

fault condition if the “blinking” signal is asserted.

For no battery condition, CHGOK

_____________ is blinking

according to the transition between charging and

charge full. The blinking frequency is determined

by the cycle of charge and discharge of the

output capacitor.

When the charge current to the battery is low or

in the event the battery is in supplement mode

caused by the insufficient input power, CHGOK

_____________

keeps low to avoid providing false charge full

indication.

Table 2 shows the ACOK

__________ and CHGOK

_____________ status

under different charge conditions.

Table 2―Charger Status Indication

ACOK

CHGOK

Charger Status

low

In charging, supplement

mode

low

high

End of charge, ISET

disable charger only.

low

blinking at

6Hz

NTC fault, timer out

high

VIN absent,

EN

disable,

thermal shutdown

Timer Setting

The MP2617A and MP2617B uses an internal

timer to terminate charge if the timer times out.

The timer duration is programmed by an external

capacitor at the TMR pin and related to the real

charge current.

The trickle mode charge time is:

TMR

Trickle _ TMR

C

t 45 (min)

0.1μF



CHG

(I 1A)

The total charge time is:

TMR

Total_TMR

C

t 6.5 (hr)

0.1μF



CHG

(I 1A)

The above equations are based on 1A charge

current. As a result of power path management

control, charge current might vary during normal

operation, under this condition, the MP2617A

and MP2617B automatically takes into account

this variation and adjust the timer period

accordingly.

When the charge current is set larger than 1A,

the safe timer period is reduced accordingly with

the same TMR capacitor. If the charge current is

reduced because of insufficient input power, the

timer period is increased proportionally by the

same rate at which the charge current is reduced.

If charge is stopped due to high system load, the

timer is temporarily suspended.

This feature avoids indicating a false trigger

indication for bad battery indication when there is

little charge current delivered to the battery as a

result of the insufficient input power. When the

timer out condition occurs, the MP2617A and

MP2617B terminates the charge at once and

CHGOK

_____________ blinks to indicate the fault status. If one

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of the following events happens, the timer is

refreshed and the MP2617A and MP2617B re-

starts the charge cycle.

 Input re-startup

 Refresh EN

_____ /ISET signal

 Auto-Recharge

NTC Thermistor

The NTC pin allows MP2617A and MP2617B to

sense the battery temperature using the Negative

Thermal Coefficient (NTC) thermistor usually

available in the battery pack to ensure safe

operating environment of the battery. A resistor

with appropriate value should be connected from

VCC to NTC and the NTC resistor is from NTC

pin to AGND. The voltage on NTC pin is

determined by the resistor divider whose divide

ratio as the different resistance of the NTC

thermistor depends on the ambient temperature

of the battery.

The MP2617A and MP2617B has an internal

NTC voltage comparator to set the upper and

lower limit of the divide ratio. If NTC pin voltage

falls out of this range it means the temperature is

outside the safe operating range,

As a result, the MP2617A and MP2617B will stop

charging and report it on indication pins.

Charging will automatically resume after the

temperature falls back into the safe range.

Thermal Protection

The MP2617A and MP2617B implements

thermal protection to prevent the thermal damage

to the IC or surrounding components. An internal

thermal sense and feedback loop will

automatically decrease the charge current when

the die-temperature rises to about 120oC. This

function is referred as charge current thermal

fold-back. This feature protects the MP2617A

and MP2617B from excessive temperature due

to high power operation or high ambient thermal

conditions. Another benefit of this feature is

charge current can be set according to the

requirement rather than worst-case conditions for

a given application with the assurance of safe

operation. The MP2617A and MP2617B will stop

charging if the junction temperature rises above

150oC as the IC enters thermal shutdown

protection.

Battery Discharge Protection

When the input power is removed or invalid, the

system load will draw power from the battery via

the battery switch. Under this condition, the

battery switch is fully on to minimize the power

loss. The MP2617A and MP2617B integrates

battery discharge protection. If the battery

discharge current is larger than the discharge

current limit threshold IDIS (5A), the current will be

regulated at the preset limited value. And if the

current increases further, the SYS voltage starts

to decrease. When VSYS drops to about 800mV

lower than VBATT, SYS short condition is detected.

Under this condition, the discharge current is

limited at 230mA. In the event of a short from

system to GND the discharge current from the

battery to the system is also limited to 230mA.

Furthermore, battery voltage UVLO is always

monitored. If the battery voltage is lower than the

battery UVLO threshold, the battery switch is

turned off immediately. This feature makes sure

the battery from over-discharged.

Dynamic Power Path Management (DPPM)

In the presence of a valid input source, the PWM

converter will supply the current to both the

system and the battery charger.

The voltage VSYS is regulated based on the value

of the battery voltage. When VBATT is higher than

3.4V, VSYS is regulated 200mv above VBATT to

charge the battery. When VBATT is lower than

3.4V, to ensure the system can still be powered

up even with a drained battery connected, VSYS is

regulated at constant 3.6V.

When the input source is overloaded, either the

current exceeds the input current limit or the

voltage falls below the input voltage limit, the

MP2617A and MP2617B then reduces the

charge current until the input current falls below

the input current limit and the input voltage rises

above the input voltage limit. If the system

current increases beyond the power allowed by

the input source, additional power will be drawn

from the battery via an on-chip 40mΩ MOSFET

working as an ideal diode.

Additionally, if the input source is removed, the

MP2617A and MP2617B will turn on the 40mΩ

FOR 4>—>\ /Vs.m>vuw_m07 \ —> BGOK="O' / Battery power system . r . 360K!“ \ Enable dams gs Imi No i Enable VREF LDO m mm dawn No power to system aname Battery Charge!

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

MP2617A, MP2617B Rev. 1.23 www.MonolithicPower.com 22

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MOSFET allowing the battery to power the

system load to keep the operation of the portable

device.

Operation Flow Chart

Taking the MP2617B for example, Figure 5

shows the operation flow chart of the MP2617B

while Figure 6 shows the operation process.

I'I'IP5'

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

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Any Limit condition

triggered?

No

Yes

VBATT>3.0V?

No

CC/CV Charge

ICHG=IBF?

Yes

Charge Full, EOC=1

TMR off,

clear the counter

DC-DC keeps work

VBATT

<VRCHG?

Yes

VSYS<VBATT-40mV?

No Yes

No

Clamp DC-DC

EAO to regulate

the part

at the limit state

Yes Trickle Charge

ICHG=10%ICC

VBATT<3.4V?

VSYS drops down,

Charge switch

is fully on

Yes

Decrease ICHG,

Keep VSYS=3.6V

No

ICHG=0?

Yes

VSYS<VBATT

-40mV?

Yes

Ideal Diode Mode:

VSYS=VBATT-65mV,

Enable discharge

current limit

VBATT

>VBATT_UVLO?

Yes

VSYS

>VBATT+40mV?

No

Battery switch shuts down,

DC-DC in over load

condition,

VSYS drops down

No

Charge in

CV mode and

ICHG<IBF

?

No

Yes

No

No Satisfy System current

Charge the battery with

remaining current

Limit condition

Removed?

Yes

No

Yes

Disable

Ideal Diode Mode

Figure 5— MP2617B Operation Flow Chart under No Fault Condition

))

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

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VIN

Normal

operation

voltage

UVLO

Thresohold

UVLO

Threshold-Hys

0

IBATT

VBATT

0

Power Path Management

ISYS -IIN_LIM

0

IIN_AVE

Input Power

Current Limit

CV Charge

Battery

Supplement

Mode

Charging

Supplement

Mode-

Discharging Charging

Auto-

Rec harging

Trickle Charge CC Charge

Battery

Full

Self-

discharging

VBATT =3.0V VBATT=3.4V

=4.0V

Power off-

discharging

VSYS

VBATT

IIN_LIM

ISYS

Figure 6— MP2617B Operation Process under No Fault Condition

I'I'II'5' RILmI

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APPLICATION INFORMATION

COMPONENT SELECTION

Setting the Input Current Limit

First the input current limit can be set by the M0

and M1 pins refer to the Table 1, the exact

current value in minimum, typical and maximum

is listed in the EC table.

Under program mode, connect a resistor from

the ILIM pin to AGND to program the input

current limit for different input ports. The

relationship between the input current limit and

setting resistor is as Equation (1) which is

shown in following again:

IN_LIM

ILIM

40000

I =1.14 (mA)

R (kΩ)



(1)

For MP2617A/B, IILIM is not over 3A.

The tolerance is ±8% of the input current limit

setting.

So for a required minimum input current limit

value, just calculate its typical value first, then

calculate the setting resistor based on Equation

(1). Also the maximum value can be calculated

according to the tolerance. 1% accuracy

resistor is used for this setting. Also, for a given

resistor of RILIM, the input current limit can be

calculated. Following table is an example:

Table 3: Example of RILIM setting

Therefore, if customer selected a 54.9k in 1%

accuracy resistor for the input current limit

setting, then the typical input current limit value

is 830.6mA, the minimum is 756.6mA and the

maximum is 906mA.

Setting the Charge Current

RISET connecting from the ISET pin to AGND

sets the charge current (ICHG). The relationship

between the charge current and setting resistor

is as Equation (2) which is shown in following

again:

CHG

SET

1800

I 1.15 (mA)

R (k )

 

(2)

For example, if the typical ICHG is designed as

2A, then the RSET is calculated at 1.05kΩ. The

tolerance of the ICHG setting is ±10%. If the

minimum or maximum charge current is

required, first the typical value should be

calculated according to the tolerance. After that,

calculate the resistor according to formula (2).

1% accuracy resistor is used for this setting.

For a given setting resistor, the charge current

can be calculated by the same way did in the

input current limit setting. Usually in USB mode,

the charge current is always set over the USB

input limit specification. Then the MP2625

regulates the input current constant at the

limitation value. Thus the real CC charge

current is not the setting value, it varies with

different input and battery voltages.

The maximum CC charge value can be

calculated as:

)A(

V

IV

I

TC

ILIMIN

MAX_CC





(3)

Where VTC is trickle charge threshold (3V) and η

is the current charge efficiency. Assume

VIN=5.5V, IILIM=1A, suppose η=83%, thus

ICC_MAX=1.52A.

Figure 7 shows a calculating charge current

curve by limiting the input current limit.

Ilim=1A

Ilim=0.825A

3V 4.2V

Battery Voltage

Charge Current

1A

2A

Ilim=1.44A

Figure 3—ICHG Variation with Different Input

Current Limit

Setting the Input Voltage Limit

The input clamp voltage is set using a resistive

voltage divider from the input voltage to VLIM

pin. The voltage divider divides the input

voltage down to the limit voltage by the ratio:

(V)

R2+R1

R2

×V=V IN_LIMVLIM

(4)

Resistor

RILIM

(kΩ)

IIN_LIM

(mA)

8%

-8%

Typ.

54.9

830.601

897.049

764.153

Min.

54.351

838.991

906.11

771.872

Max.

55.449

822.377

888.168

756.587

I'IIIE' LMAX

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Thus the input voltage is:

(V)

R2

R2+R1

×V=V VLIMIN_LIM

(5)

The voltage clamp reference voltage VVLIM is

1.52V, and a typical value for R2 can be 10kΩ.

With this value, R1 can be determined by:

(V)

V

V-V

×R2=R1

VLIM

VLIMIN_LIM

(6)

For example, for a 4.65V input limit voltage, R2

is 10kΩ, and R1 is 20.6kΩ.

The minimum value and the maximum value of

the input voltage limit can be calculated

according to the accuracy of the resistor and

the tolerance of VVLIM. 1% accuracy resistors

are used for R1 and R2.

Setting the System Voltage

The system voltage can be regulated to any

value between 4.08V to 4.4V (MP2617B) by the

resistor divider on SYSFB pin as R6 and R7 in

Figure 10.

SYS SYS _ REF

R6 R7

VV R7





(7)

Where VSYS_REF is 1.152V, the reference voltage

of SYS. With a typical value for R7, 10kΩ, R6

can be determined by:

SYS SYS _ REF

SYS _ REF

VV

R6 R7 (V)

V





(8)

For example, for a 4.2V system voltage, R7 is

10kΩ, and R6 is 26.5kΩ. 1% resistors are

selected for the R5 and R6.

Be noted that, the minimum VSYS is limited to be

higher than the maximum value of the auto-

recharge threshold which is 4.05V.

Selecting the Inductor

Inductor selection trades off among cost, size,

and efficiency. A lower inductance value

corresponds to a smaller size, but results in

higher ripple currents, higher magnetic

hysteretic losses, and higher output

capacitances. From a practical standpoint, the

inductor ripple current does not exceed 30% of

the maximum load current under worst cases

conditions. For example, if the ICHG is setting to

3A in MP2617B, then, ΔIL is general set at 0.9A.

However, for the light load condition, the

inductor ripple current will be very small which

may cause unstable operation due to the peak

current mode control of the IC. For stable

operation, the experienced minimum limit value

for inductor current ripple is 0.5A. Therefore, the

inductor current ripple is the maximum one of

30% times ICHG and 0.5A.

And the inductance can be calculated according

to Equation (9):





_()

IN SYS SYS

L MAX IN S

V V V

LI V f MHz

(H) (9)

The peak current of the inductor is calculated

as Equation (10):

)

2

ripple%

1(II )MAX(LOADPEAK 

(mA) (10)

Where VIN, VSYS, and fS are the typical input

voltage, the output voltage, and the switching

frequency, respectively.

Following Table 4 provides the selection guide

of the inductance based on different input

voltage.

Table 4: Inductance Selection Guide under different Input Voltage

SPEC

Inductance Selection

VIN



()

IN SYS SYS

L IN S

V V V

LI V f MHz

ΔIL=max (0.3*ICHG,0.5A)

ΔILMIN=0.5A

ΔILMAX=0.9A

LMIN

(μH)

LMAX

(μH)

L

(μH)

Saturation

Current (A)(5)

DCR

(mΩ)

Package

5V

0.367

1.25

1.0

>3.95

<50

Application

Required

9V

1.5

2.8

2.2

>3.95

<50

Application

Required

NOTE:

5) Saturation Current of the inductor should be higher than the IPEAK, add 0.5A margin here.

I'IIIE'

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

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Selecting the Input Capacitor

The input capacitor C1 from the typical

application circuit absorbs the maximum ripple

current from the PWM converter, which is given

by

MAX_IN

TCMAX_INTC

MAX_CCMAX_RMS V

)VV(V

II 



(A) (11)

For ICC_MAX=2A, VTC=3V, VIN_MAX=10V, the

maximum ripple current is 1A. Select the input

capacitors so that the temperature rise due to

the ripple current does not exceed 10°C. Use

ceramic capacitors with X5R or X7R dielectrics

because of their low ESR and small

temperature coefficients.

For most applications, use a 10µF capacitor.

Besides, usually a small cap with at least 1uF

(C1) from IN to GND is required to be put as

much close as possible to the IC. For the input

voltage is high to 10V, consider the spike when

input insert, select the input capacitors (both the

22uF and 1uF) in 25V rating.

Selecting the Output Capacitor

The output capacitor CSYS from the typical

application circuit is in parallel with the SYS

load. CSYS absorbs the high-frequency switching

ripple current and smoothes the output voltage.

Its impedance must be much less than that of

the system load to ensure it properly absorbs

the ripple current.

Use a ceramic capacitor because it has lower

ESR and smaller size that allows us to ignore

the ESR of the output capacitor. Thus, the

output voltage ripple is given by:

%

Lf2C8

V

1

V

r2

S

IN

SYS











(12)

In order to guarantee the ±0.5% system voltage

accuracy, the maximum output voltage ripple

must not exceed 0.5% (e.g. 0.1%). The

maximum output voltage ripple occurs at the

minimum system voltage and the maximum

input voltage.

The output capacitor can be calculated with

Equation (13):

SYS _MIN

IN

SYS 2

S

V

1V

C8 f L r



   

(13)

When SYSFB pin is floating, output voltage

ripple is the main concern to select the output

capacitor (CSYS), refer to Table 5 for detail

selection guide about the SYS capacitance

selection under typical inputs.

Table 5: SYS Capacitance Selection Guide

NOTE:

6) For different voltage rating, capacitance will have different DC bias characteristic. Suppose a general condition, capacitance drops

40% under VSYS=4.4V under 10V rating, and 50% at 6.3V rating.

SPEC

SYS Capacitance (CSYS) Selection

VIN

SYS

IN

SYS 2

S

V

1V

C8 f L r



   

Δr=0.1%

L=1μH @VIN=5V

L=2.2μH @VIN=9V

CSYS_MIN (μF) 6)

When SYSFB is

Floating

CSYS_MIN (μF) 6)

When SYSFB

is Programmed

Temperature

Characteristic

Package

5V

13.6

20

X5R;X7R

Application

Required

9V

13.3

20

X5R;X7R

Application

Required

I'I'IPS' Rn VCC 2 LOW Temp Thrahoh / v.“l NT I \ é; nun Temp mama an

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When SYSFB is programmed using external

resistors, the control loop function is changed.

A zero point is added around the cross over

frequency of the DC gain, and this may result in

the phase margin varied a lot, which may cause

the unstable operation. To avoid this condition,

a minimum capacitance requirement should be

satisfied to make the pole point to compensate

the zero point. This minimum capacitance is

20uF for a general application.

So, for the SYSFB programmed condition, the

CSYS should be selected as max (CSYS_MIN,

20uF), CSYS_MIN is calculated from the formula of

equation (13), as shown in Table 5. For better

stability margin, select a 47uF ceramic

capacitor with 6.3V and above voltage rating as

the output capacitor in this case.

Resistor Choose for NTC Sensor

Figure 8 shows an internal resistor divider

reference circuit to limit the low temperature

threshold and high temperature threshold at

65%·VCC and 33.5%·VCC, respectively. For a

given NTC thermistor, select appropriate RT1

and RT2 to set the NTC window:

T2 NTC_Cold THL

T1 T2 NTC_Cold

R //R V65%

R R //R VCC





(14)

T2 NTC_Hot THH

T1 T2 NTC_Hot

R //R V33.5%

R R //R VCC





(15)

RNTC_Hot is the value of the NTC resistor at high

temperature of the required temperature

operation range, and RNTC_Cold is the value of

the NTC resistor at low temperature.

The two resistors, RT1 and RT2, allow the high

temperature limit and low temperature limit to

be programmed independently. With this

feature, the MP2625B can fit most type of NTC

resistor and different temperature operation

range requirements.

RT1 and RT2 values depend on the type of the

NTC resistor:

NTC_HotNTC_Cold

T2 R.42250-R1225.0

RR.30

R





(16)

)RR(2275.0

RR0.3

R

NTC_HotNTC_Cold

NTC_ColdNTC_Hot

T1 





(17)

For example, for the thermistor NCP18XH103,

it has the following electrical characteristic:

At 0°C, RNTC_Cold = 27.445kΩ;

At 50°C, RNTC_Hot = 4.1601kΩ.

The following equations are derived assuming

that the NTC window is between 0°C and 50°C.

According to the above equations to calculate

RT1=7.15kΩ and RT2=25.5kΩ.

Figure 4—NTC Function Block

PCB Layout Guideline

It is important to pay special attention to the

PCB layout to meet specified noise, efficiency

and stability requirements. The following design

considerations can improve circuit performance:

1) Route the power stage adjacent to their

grounds. Aim to minimize the high-side

switching node (SW, inductor), trace lengths in

the high-current paths and the current sense

resistor trace.

Keep the switching node short and away from

all small control signals, especially the feedback

network.

Place the input capacitor as close as possible

to the IN and PGND pins.

Place the output inductor close to the IC and

connect the output capacitor between the

inductor and PGND of the IC.

2) For high-current applications, the balls for the

power pads (IN, SW, SYS, BATT and PGND)

should be connected to as much copper in the

board as possible. This improves thermal

performance because the board conducts heat

away from the IC.

I'I'IIE'

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

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3) The PCB should have a ground plane

connected directly to the return of all

components through vias (two vias per

capacitor for power-stage capacitors, one via

per capacitor for small-signal components). It is

also recommended to put vias inside the PGND

pads for the IC, if possible. A star ground

design approach is typically used to keep circuit

block currents isolated (high-power/low-power

small-signal) which reduces noise-coupling and

ground-bounce issues. A single ground plane

for this design gives good results. With this

small layout and a single ground plane, there is

no ground-bounce issue, and having the

components segregated minimizes coupling

between signals.

I'IIIE' “—TT a \ i8 J L3?

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

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TYPICAL APPLICATION CIRCUITS

L

CHGOK

ACOK

NTC

EN

AGND

TMR

BATT

BST

SW

OFF

ON

C3

M1

5V Input IN

M0

VCC

VILIM

SYS

ISET

RISET

CSYS

CBATT

SYS Load

C2

MP2617B

RILIM

SYSFB

ILIM

R1

R2

R3

R4

CIN

0

PGND

vBATT

ICHG

RT1

RT2

CTMR

C1

10uF

1uF

10k

21k

1uF

10k

2k

100nF

30.9k

1.05k

100nF

1.0uH

22uF

Figure 9: Typical Charge Application Circuit for 5V input with NTC Resistor Fixed

Table 6: The Key BOM of Figure 9.

Qty

Ref

Value

Description

Package

Manufacture

1

CIN

10μF

Ceramic Capacitor;10V;

X5R or X7R

1206

Any

1

C1

1μF

Ceramic Capacitor;10V;

X5R or X7R

0603

Any

1

C2

1μF

Ceramic Capacitor;6.3V;

X5R or X7R

0603

Any

1

C3

100nF

Ceramic Capacitor;16V;

X5R or X7R

0603

Any

1

CTMR

100nF

Ceramic Capacitor;6.3V;

X5R or X7R

0603

Any

2

CSYS,CBATT

22μF

Ceramic Capacitor;10V;

X5R or X7R

1206

Any

2

RT1,RT2

10k

Film Resistor;1%

0603

Any

1

L1

1.0μH

Inductor;1.0uH;Low

DCR;ISAT>2.8A

SMD

Any

I'IIIE'

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

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TYPICAL APPLICATION CIRCUITS

L

CHGOK

ACOK

NTC

EN

AGND

TMR

BATT

BST

SW

OFF

ON

C3

M1

9V Input IN

M0

VCC

VILIM

SYS

ISET

RISET

CSYS

CBATT

SYS Load

C2

MP2617B

RILIM

SYSFB

ILIM

R1

R2

R3

R4

CIN

0

PGND

vBATT

ICHG

RT1

RT2

CTMR

C1

22uF

1uF

10k

21k

1uF

10k

2k

100nF

30.9k

1.05k

100nF

2.2uH

22uF

C4

4.7uF

R6 R7

26.5k

10k

R5 100k

Figure 10: Typical Charge Application Circuit for 9V Input and 1.5A Input Current Limit

Table 7: The Key BOM of Figure 10.

Qty

Ref

Value

Description

Package

Manufacture

1

CIN

22μF

Ceramic Capacitor;16V;

X5R or X7R

1206

Any

1

C1

1μF

Ceramic Capacitor;16V;

X5R or X7R

0603

Any

1

C2

1μF

Ceramic Capacitor;

6.3V; X5R or X7R

0603

Any

1

C3

100nF

Ceramic Capacitor;25V;

X5R or X7R

0603

Any

1

C4

4.7μF

Ceramic Capacitor;

10V; X5R or X7R

0603

Any

1

CTMR

100nF

Ceramic Capacitor;

6.3V;X5R or X7R

0603

Any

2

CSYS,CBATT

22μF

Ceramic Capacitor;10V;

X5R or X7R

1206

Any

1

R6

26.5k

Film Resistor;1%

0603

Any

3

RT1,RT2,R7

10k

Film Resistor;1%

0603

Any

1

L1

2.2μH

Inductor;2.2μH;Low

DCR;ISAT>6A

SMD

Any

I'IIIE' TOP VIEW m {EF{7_E|_ELELE|_ SIDE VIEW RECOMMENDED LAND PA'I'YERN 44 307mm VIEW NOTE: UDE

MP2617A, MP2617B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH

NOTICE: The information in this document is subject to change without notice. Users should warrant and guarantee that third

party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not

assume any legal responsibility for any said applications.

MP2617A, MP2617B Rev. 1.23 www.MonolithicPower.com 32

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PACKAGE INFORMATION

QFN-20 (3mmX4mm)

PACKAGE OUTLINE DRAWING FOR 20L FCQFN (3X4MM)-5

MF-PO-D-0147 revision 0.0

SIDE VIEW

BOTTOM VIEW

NOTE:

1) ALL DIMENSIONS ARE IN MILLIMETERS.

2) EXPOSED PADDLE SIZE DOES NOT INCLUDE

MOLD FLASH.

3) LEAD COPLANARITY SHALL BE 0.10

MILLIMETERS MAX.

4) JEDEC REFERENCE IS MO-220.

5) DRAWING IS NOT TO SCALE.

PIN 1 ID

MARKING

TOP VIEW

PIN 1 ID

INDEX AREA

RECOMMENDED LAND PATTERN

PIN 1 ID

0.10 X 45? TYP

0.10 X 45?

MP2617A, MP2617B Datasheet by Monolithic Power Systems Inc.

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