Hi Team,
We look for a step-up RGB+W led driver with following specifications
Vin (min) – 3.0V
Vin (max) – 5.0V
Drive : Constant current by PWM (each led independently)
Current : 100 mA per led
We need 3 separate channels to drive the R,G & B leds with independent PWM to create different colours.
The White led is only used when RGB is OFF, so we can share it with one of the RGB channels using a Mosfet.
The leds have the maximum Vf voltage as indicated below
Red – 2.6V
Green – 3.8V
Blue – 3.8V
White – 3.6V
We only find multichannel drivers for low current RGB leds (about 20mA), and obviously we have no budget to use a single driver for each led for 100 mA.
We can use switch technology, or charge-pump depending of price and efficiency.
Any help like an Application Note or suggestion of any circuit where we can drive the 3 leds with a single channel driver is welcome.
regards
