The MIC3263 is a high-efficiency pulse-width modulation (PWM) boost switching regulator that is optimized for constant-current WLED driver backlighting applications. The MIC3263 drives six channels of up to ten WLEDs per channel. Each channel is matched in current to within ±3% for constant brightness across the screen and can be programmed from 15mA to 30mA.

The MIC3263 provides a very flexible dimming control scheme with better accuracy and noise immunity. The dimming frequency can be set to any value between 100Hz and 20kHz by an external resistor. The dimming ratio is determined by the duty cycle of a dimming ratio control input signal and can be set to one of 16 levels with a minimum ratio of 1%.The LED dimming current is set by an external resistor to allow programming of LED current between 15mA and 30mA.

The dimming ratio of the MIC3263 is fixed to 16 log levels to better match the sensitivity of the human eye. Each of the dimming levels has hysteresis to avoid skipping between levels and allow for high noise immunity.

The MIC3263 has a programmable PWM switching frequency from 400kHz to 1.8MHz to allow small inductor sizes. The 6V to 40V wide input voltage range of MIC3263 allows direct operation from 6V or high cell count Li-Ion batteries commonly found in notebook computers. The MIC3263 is available in a low-profile 24-pin 4mm x 4mm MLF??package and has a junction temperature range of -40°C to -125°C.

  6V to 40V wide input voltage range

  Drives six channels of up to 10 white LEDs

  Programmable WLED current from 15mA to 30mA

  Highly reliable operation with open and short LEDs

  Accurate 16 dimming log levels sets the dimming ratio from 1% to 100%

  Flicker-Free Dimming filters the jitter from the dimming control input signal and eliminates dimming flicker

  Allows external dimming control

  Accurate LED channel current matching ±3%

  Accurate initial LED current setting ±2%

  Programmable switching frequency from 400kHz to 1.8MHz

  High efficiency up to 90%

  Low (<40μA) shutdown current over temperature

  Over temperature protection

  Programmable over-voltage protection

  -40°C to -125°C junction temperature range

  Available in 24-pin 4mm x 4mm MLF??package