1x/1.5x Auto-Adjust Charge Pump 4-Channel
White LED Driver with Two Dimming Modes
The PT4303 is a 4-channel 1x/1.5x auto-adjust charge pump white LED driver with three
dimming modes. Auto-adjust charge pump achieves high efficiency for Li-Ion battery supply.
The three LED dimming modes enable users to dim the four LEDs all together or individually.
Only a few external components (two flying capacitors and two filter capacitors at VIN and VOUT)
are needed, which makes the PT4303 ideally suited for mobile applications.
The current through the LED can be set by an external resistor. The four LEDs can be turned
on and off individually or in a group of two to four through the two control terminals, which can
also be used to dim the LEDs by applying PWM control signals.
Built-in soft-start circuit prevents the inrush current from the power supply during power on and
1x/1.5x mode change. The thermal shutdown and current limiter prevent the PT4303 from
being damaged by a high-level current through it. A shutdown current of less than 1uA makes
the battery last longer. The PT4303 is available in QFN-16 package.
♦ 3V-5.5V input voltage
♦ 1x/1.5x auto-adjust charge pump
♦ Set LED current by external resistor
♦ Dimming LED by PWM signal through 2 control terminal
♦ LED fault detection
♦ <3% current mismatch
♦ No inductor
♦ Less than 1uA shutdown current
♦ Built-in soft-start and soft mode decision
♦ Cell phones
♦ Laptop computers and PDAs
♦ Digital cameras
♦ Small LCD displays
♦ Programmable current sink