ILD4035 24V BOARD: 350mA @ 40 Max, 4.5 ~ 40V in

This document contains information about the LED-Less Demonstration Board for ILD4035. ILD4035 is a hysteretic step-down LED driver. Please refer to the datasheet for the pins descriptions, functions descriptions and specifications.

The ILD4035 Demonstration Board has two versions. Version ILD4035 24V Board’s sense resistance is optimized to drive a string of 6 series LEDs at 350mA (max current) with an input voltage of 24V. Version ILD4035 12V Board’s sense resistance is optimized to drive a string of 3 series LEDs at 350mA (max current) with an input voltage of 12V.

ILD4035 maintains a constant current through a string of LEDs as long as the input voltage exceeds the sum of the forward voltages of the LEDs in the string by at least 3V. The maximum input voltage for this demonstration board must not exceed 30V; this restriction is due to the Schottky diode installed which has a reverse breakdown voltage of 30V. If there is a need to test the board with a maximum supply voltage of 40V, please replace the Schottky diode SD1 with a suitable breakdown voltage.

The ILD4035 incorporates the following protection features: Over-voltage protection, temperature protection and an over-current protection.

The board includes a “Multifunctional Pin” input terminal for digital or analog dimming control signal. PWM dimming frequencies up to 300Hz at 100:1 contrast ratio and at 100Hz contrast ratio of 300:1 are possible.

The complete demonstration board schematic is shown in Figure 2. Typical waveforms and performance curves are shown in Figure 4 to Figure 8.

Although a wide variety of LED combinations and currents can be driven with the ILD4035, the sense-resistors have to be altered to achieve maximum current of 350mA and inductance has to be changed to attain recommended switching frequencies below 500 kHz.