ON Semiconductor's 6W LED Driver for Larger LCD Panel Backlighting

As the company’s first multi-channel boost device, the CAT4106 is capable of driving as many as 40 white LEDs – or four strings of 10 LEDs with up to 36 volts (V) per string - for a total of 6 W of LED output power. Additionally, the device enables designers to maximize backlighting efficiency and reduce space via its built-in diagnostics functions, which automatically adjust the output voltage to drive the highest forward voltage (Vf) string with the minimum head room voltage.

The on-chip diagnostic circuit allows designers to set the minimum and maximum voltage limits for the acceptable range of operation for LED strings through external programming resistors. Any channel which does not regulate within the set range of Open Circuit or Short Circuit LED will be detected and flagged on the FAULT logic output (active-low, open-drain). The device also provides thermal shutdown and overvoltage protection (OVP).

The CAT4106 features low dropout LED channels of 500 millivolts (mV) at 175 milliamps (mA) and a high-frequency pulse width modulation (PWM) interface, which supports multiple frequencies up to 2 kilohertz (kHz), providing precise, high-resolution dimming control while the device remains fully biased.