LCD Backlight Luminance Auto-control Circuit (Visible Light Luminance Sensor LX1970) Diagram

Published:2011/7/7 8:36:00 Author:Vicky | Keyword: LCD Backlight, Luminance Auto-control Circuit , Visible Light Luminance Sensor | From:SeekIC

When it turns dark, LX1970 will automatically start up the LDC backlight to make white LED luminous. Luminance auto-control circuit is shown in the picture. The maximum and minimum value of the luminance can be controlled and set by resistances R1 and R2. The responding time and leaching of disturbance of 50Hz power grid can be adjusted by changing the capacity of capacitance C. LX1970 adopts +3．3 to +5V power supply. When only SRC end is used, the SNK end should hang in air. Suppose that the white LED is driven by 0．25～1．25V output voltage, then 0.25V is the minimum luminance value of LED while 1.25 is the maximum value.



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