Alc - LG KF510C Service Manual

3. TECHNICAL BRIEF

3.11 ALC

The automatic luminance control (ALC) circuit adjusts the LED dimming by changing the LED current
automatically in response to the brightness of the surroundings. An external photodiode or similar
luminance sensor must be connected for the ALC automatic control to function. The luminance sensor
is connected to PD and must be set to increase the PD input current in response to increasing
luminance of the surroundings. In the typical application circuit in section 13, the SM8152A VREF
terminal is used and the luminance sensor photodiode is connected between PD and VREF
LGE Internal Use Only
Figure 17 Average Iout vs Lux on photo sensor
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