Patent ID: 7589704
Filing Date: 2009-09-15
Classification: G09G

Abstract:
1. A circuit to drive a backlight for a display comprising: a backlight device driver; a DC-to-DC converter; and a smart talk mechanism to feed back adjustment information from the driver to the DC-to-DC converter, thereby enabling the DC-to-DC converter to adjust an input voltage for at least one illumination source backlighting the display for increasing the power efficiency; wherein the smart talk mechanism uses a voltage at the device driver to determine the adjustment information; wherein the backlight device drives at least one LED for the backlight, the feedback mechanism reducing the voltage at a cathode of the LED; wherein the reduction of the cathode voltage is done by continuously adjusting an anode voltage; wherein the driver output is used to produce the adjustment information and feed that back to the DC-to-DC converter; and wherein if the anode voltage is high, then the DC-to-DC converter will decrease its output to lower the cathode voltage and hence lower the anode voltage as well, if the anode voltage is low, then the DC-to-DC converter will increase its output to raise the cathode voltage and hence raise the anode voltage as well.