Backlight panel LED driver ICs include voltage step-up controller

December 24, 2013 // By Graham Prophet
Ams has posted detail of a series of high precision LED controllers with PWM input for driving external bipolar transistors in LED backlight panels, also optimised for 2D and 3D operation in TV applications.

AS3834/3834B are 4 channel devices with integrated step-up controller to provide the necessary output voltage for the LED string supply. The SMPS feedback control optimises the power efficiency by adjusting the LED string supply voltage. Output current is up to 270mA per channel and built-in safety features include under-voltage and thermal shutdown as well as open and short LED detection. 

The AS3833 is a 6 channel LED controller with a similar specification, delivering output current up to 250mA per channel.

Features include;
Supply voltage range: 12V to 50V;
Absolute current accuracy ± 0.8%;
Channel to channel accuracy ±0.6%;
1 PWM input with internal phase shift;
Open LED detection and auto-disconnect;
Short LED protection and auto-turnoff;
Undervoltage shutdown;
Temperature shutdown;
Temperature supervision of external BJT;
BJT Beta compensation;
SMPS feedback control;
DCDC Softstart Function;
Over Voltage Protection (OVP).

Package options include SOIC-28 and TQFP-32