PT4301

PT4301, PT4303 4 Channel 1×/1.5× Auto-Adjust Charge Pump White LED Driver 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 the PT4301, or a two-bit digital code at the two control inputs in the PT4303. Therefore, individual dimming control can be realized by applying PWM signals at those control inputs. The built-in soft-start circuit eliminates the inrush current during power on and 1x/1.5x mode switching. Thermal shut down and current limiter prevent the PT4301/03 from being damaged by high level current through the dev...