6W Four Channel LED Driver

CAT4106 is an integrated Four channel LED driver (multi-channel LED driver) and high power dc-dc converter 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 Four channel LED driver automatically adjusts the output voltage to drive the highest forward voltage string with the minimum headroom voltage maximizing the efficiency.

6W Four Channel LED Driver Circuit diagram

High resolution dimming control is achieved by the EN/PWM logic pin which supports multiple frequencies. This ensures precise PWM dimming control while the device remains fully biased. In addition, when held at logic low, the device to enter a full shutdown 'zero' current mode. External programming resistors set the minimum and maximum voltage limits for the acceptable 'window of operation' for LED strings. Any channel which fails to regulate within the window (Open or Short LED) is detected and flagged on the FAULT logic output (active low, open-drain).

Main features of CAT4106 led driver are : four LED channels with tight current matching , integrated dc-dc boost converter , up to 6 W LED total output power , up to 92% efficiency , low dropout LED channels (500 mV at 175 mA) , high frequency PWM interface (up to 2 kHz) ,adjustable short/open LED detection The CAT4106 requires small ceramic capacitors of 1 μF on the VIN pin (C1), 4.7 μF on the inductor input (C2), and 10 μF on the output (C3). Under normal condition, a 4.7 μF input capacitor (C2) is sufficient. A 47 μH inductor is recommended with current rating of 1 A or higher and 1A rated Schottky diode .

A typical value for resistor R7 and R5 is around 20 kΩ. R6 and R4 can be calculated as follows:

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