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Reducing power consumption in a liquid crystal display

  • US 9,407,257 B2
  • Filed: 09/14/2007
  • Issued: 08/02/2016
  • Est. Priority Date: 04/18/2007
  • Status: Active Grant
First Claim
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1. An apparatus, comprising:

  • a bias voltage generator to generate a plurality of bias voltages; and

    a drive buffer to drive a passive liquid crystal display (LCD) pixel or segment from a particular one of the bias voltages, wherein the drive buffer actively drives the passive LCD segment or pixel in a first phase, and wherein the drive buffer comprises;

    a first buffer configured to actively drive a voltage, applied to the passive LCD pixel or segment, to a threshold level that is different from the particular one of the bias voltages, wherein the first buffer includes a current source that is configured to drive the voltage applied to the passive LCD pixel or segment to the threshold level; and

    a second buffer in parallel with the first buffer configured to actively further modify the voltage, applied to the passive LCD pixel or segment, from the threshold level to approximate the particular one of the bias voltages;

    wherein the drive buffer is configured to actively drive the passive LCD segment or pixel by adjusting the voltage, applied to the passive LCD pixel or segment, to approximate the particular one of the bias voltages, and by compensating a leakage associated with the passive LCD pixel or segment to provide a constant voltage at the passive LCD pixel or segment in a low-drive mode; and

    wherein the second buffer is activated during the low-drive mode.

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