MIC3263 Datasheet, PDF (1/32 Pages) Micrel Semiconductor – Six-Channel WLED Driver for Backlighting Applications with Flicker-Free Dimming

MIC3263
Six-Channel WLED Driver for
Backlighting Applications with
Flicker-Free Dimming
General Description
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 400 KHz to 1.8 MHz 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.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
• 6V to 40V wide input voltage range
• Drives 6 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
Applications
• White LED driver for backlighting
• Notebooks
• LCD Panels and Monitors
• Multimedia players
• Navigation equipment
• Gaming systems
• Video poker
• Slot machines
_________________________________________________________________________________________________________________________
MLF is a registered trademark of Micrel, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
January 2010
M9999-012110