GENERAL DESCRIPTION
The PT4301/03 is a 4-channel 1x/1.5x auto-adjust charge pump white LED driver that achieves high efficiency for Li-Ion battery supply. The LED current can be set by an external resistor. Only one small resistor and four 1µF small ceramic capacitors are needed as external components to construct a LED driver, which makes the PT4301/03 an ideal choice for portable applications. The LED fault detection circuit in the PT4301/03 improves the reliability of the system. The PT4301/03 has three dimming modes that allow users to adjust the brightness of the four LEDs individually or all together. The first two dimming modes can be controlled through the EN/SET pin either by applying a serial digital code, in which case the LED currents can be set with eight levels of up to 20mA, or by providing a pulse-width-modulation (PWM) signal input. The third dimming mode relies on the feature that the four LEDs can be turned on and off selectively by a three-bit digital code at the three control inputs in Therefore, individual dimming control can be realized by applying PWM signals at those control inputs.
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