MIC2297-42YML EV: 1.2A @ 42V Max, 2.5 ~ 10V in

The MIC2297 is a PWM White LED driver optimized for 6 to 10 series WLEDs. With an output voltage of up to 42V and a guaranteed 1.2A on the internal power switch, the MIC2297 can easily drive 10 WLEDs at 20mA continuous current. The MIC2297 features WLED brightness control using the BRT pin and has output over voltage protection to protect the device in case the WLEDs are disconnected unexpectedly.

The MIC operates at a default feedback voltage of only 200mV. The low feedback voltage reduces the power dissipation from the external current set resistor and increases total operating efficiency.

When brightness control is required, the MIC2297 features brightness control by applying a DC voltage to the BRT pin. When applying a DC voltage to the BRT pin, the feedback voltage is equal to the BRT voltage divided by 5. This feature essentially increases or decreases the feedback voltage from its default value (200mV), changing the WLED current to control the brightness.

Alternatively, a PWM signal may also be applied to the BRT pin for brightness control. When a PWM signal (1kHz recommended) is applied to the BRT pin, the WLEDs are dimmed depending on the duty cycle and the peak voltage of the signal. The PWM frequency can range from 1kHz to 1MHz. The selected PWM frequency does not affect the WLED brightness. Assuming a 1V PWM signal is applied, as the duty cycle decreases, the feedback voltage decreases, thus reducing the WLED current.

The MIC2297 evaluation board requires an input power source that is capable of providing greater than 1.2A at 2.5V.