LP3958 Datasheet, PDF (15/28 Pages) National Semiconductor (TI) – Lighting Management Unit with High Voltage Boost Converter

Backlight Drivers
LP3958 has 2 independent backlight drivers. Both drivers are regulated constant current sinks. LED current for both LED strings
are controlled by the 8-bit current mode DACs with 0.1 mA step. MAIN and SUB LEDs can be also controlled with one DAC
(MAIN) for better matching allowing the use of larger displays having up to 8 white LEDs by setting DISPL bit to 1.
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MAIN output for 4 LEDs (DISPL = 0)
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SUB output for 2 LEDs (DISPL = 0)
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MAIN and SUB outputs for 8 LEDs (DISPL = 1)
PWM CONTROL
External PWM control is enabled by writing 1 to EN_MAIN_PWM and/or EN_SUB_PWM bits in register address 2BH. GPIO[0]
pin is used as external PWM input when EN_PWM_PIN is set high. PWM input is active high, i.e. LED is activated when in high
state.
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