Charge pump with CABC mode for smartphone LED backlighting
ON Semiconductor has introduced the CAT3649, a six channel quad mode LED driver for use in the latest smartphones and other consumer handheld applications. According to the company, the quad mode architecture, coupled with Content Adaptive Brightness Control (CABC) ensures market leading efficiency in LED backlighting using only external capacitors.
The CAT3649 has four charge pump modes; 1, 1.33, 1.5 and 2x. The inclusion of a 1.33x mode is said to increase efficiency by up to 10% compared to traditional charge pump LED drivers using 1.5x operation.
The pump has been designed to support a range of input voltages, from 2.4 to 5.5V. The LED current can be adjusted by analogue dimming in 32 linear increments via a single wire interface. Further adjustment can be carried out through PWM, which is compatible with CABC for frequencies from 100Hz to 200kHz.
