Date: 02/05/2012

HT7938A/HT7939A white light LED drivers from Holtek for backlight applications

Holtek has released the HT7938A and HT7939A white light LED drivers. These drivers increase the application coverage of WLED backlight small size panels and support PWM dimming frequency of up to 200 kHz.

The HT7938A use a 40V high voltage process and is able to drive up to 10 WLEDs in series. Using LEDs in series means that the individual LED currents are identical resulting in the same generated illumination level from each WLED. Two feedback voltages of 200mV or 300mV provide a variety of design options.

The HT7939A now upgrades the internal MOSFET drive current of 950mA up to a value of 1200mA. The device can drive up to 39 LEDs, in a combination of 3-series and 13-parallel.

Both the HT7938A and HT7939A include over temperature and over current protection circuits as well as an under voltage lockout (UVLO) function.