A very simple LED driver electronic project can be designed using the CAT3649 high efficiency quad mode R fractional charge pump IC that can drive up to six LEDs. The inclusion of a 1.33x fractional charge pump mode increases the device efficiency by up to 10% over traditional 1.5x charge pumps with no added external capacitors.
Low noise input ripple is achieved by operating at a constant switching frequency which allows the use of small external ceramic capacitors. The multi−fractional charge pump supports a wide range of input voltages from 2.4 V to 5.5 V.
Using the CAT4106 integrated multi-channel LED driver and high power dc-dc converter manufactured by ON Semiconductor can be designed a very simple and high efficacy LED driver suitable for powering backlighting applications up to a total of 6 watts.
Up to four matched LED strings can be accurately programmed with uniform drive current set by a single external resistor.
The CAT4106 driver automatically adjusts the output voltage to drive the highest forward voltage string with the minimum headroom voltage maximizing the efficiency.
The TCA62735AFLG is a charge pump type DC DC Converter specially designed for constant current driving of white LED.
This IC can outputs LED current 120mA or more to 2.8-4.2V input.
This IC observes the power-supply voltage and the output voltage, and does an automatic change to the best of step up mode 1, 1.5 or 2 times. It is possible to prolong the battery longevity to its maximum.
This IC is especially for driving back light white LEDs in LCD of PDA, Cellular Phone, or Handy Terminal Equipment.