LP5520 Datasheet, PDF (1/34 Pages) National Semiconductor (TI) – RGB Backlight LED Driver

May 2007
LP5520
RGB Backlight LED Driver
General Description
The LP5520 is an RGB backlight LED driver for small format
color LCDs. RGB backlight enables better colors on the dis-
play and power savings compared with white LED backlight.
LP5520 offers small and simple driver solution without need
for optical feedback. Calibration in display module production
can be done in one temperature. LP5520 produces true white
light over wide temperature range. Three independent LED
drivers have accurate programmable current sinks and PWM
modulation control. Using internal calibration memory and
external temperature sensor, the RGB LED currents are ad-
justed for perfect white balance independent of the brightness
setting or temperature. The user programmable calibration
memory has intensity vs. temperature data for each color.
This white balance calibration data can be programmed to the
memory on the production line of a backlight module.
The device has a magnetic boost converter that creates up to
20V LED supply voltage from the battery voltage. The output
can be set at 1V step from 5V to 20V. In adaptive mode the
circuit automatically adjusts the output voltage to minimum
sufficient level for lowest power consumption.
Temperature is measured using an external temperature sen-
sor placed close to the LEDs. The second ADC input can be
used e.g. for ambient light measurement.
LP5520 is available in 25 pin microSMD™ package.
Features
■ ^{Temperature compensated LED intensity and color}
■ ^{Individual calibration coefficients for each color}
■ ^{Color accuracy ΔX and ΔY ≤ 0.003}
■ ^{12 bit ADC for measurement of 2 sensors}
■ ^{Adjustable current outputs for R, G and B LED}
■ ^{0.2% typical LED output current matching}
■ ^{PWM control inputs for each color}
■ ^{SPI and I2C compatible interface}
■ ^{Stand-alone mode with 1 wire control}
■ ^{Sequential mode for one color at a time}
■ ^{Magnetic high efficiency boost converter}
■ ^{Programmable output voltage from 5V to 20V}
■ ^{Adaptive output voltage control option}
■ ^{< 2 µA typical shutdown current}
■ ^{MicroSMD-25 package, 2.77 × 2.59 × 0.6mm}
Applications
■ ^{Color LCD display backlighting}
■ ^{LED lighting applications}
■ ^{Non-linear temperature compensation}
■ ^{Ambient light compensation}
Typical Application
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