Computer graphics processing and selective visual display system – Display driving control circuitry
Reexamination Certificate
2011-03-08
2011-03-08
Vo, Tuyet Thi (Department: 2821)
Computer graphics processing and selective visual display system
Display driving control circuitry
C345S211000, C345S212000, C345S066000, C345S102000, C315S2090SC, C315S224000, C315S291000, C315S247000
Reexamination Certificate
active
07903105
ABSTRACT:
Methods and apparatus to improve efficiency in cold cathode fluorescent light (CCFL) controllers using a full bridge resonant implementation. The secondary of a transformer drives the CCFL, with the primary of the transformer being driven through a capacitor from a full bridge. The bridge alternately and repetitively connects the capacitor and primary between power supply connections, across one of the power supply connections, between the power supply connections with an alternate polarity and again across one of the power supply connections. Instead of switching from across one of the power supply connections to between the power supply connections when the primary current is near zero, a delay is intentionally imposed before switching. This significantly improves the operating efficiency of a backlighting system. In preferred embodiments, the delay is made power supply voltage dependent.
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Lan Rayleigh
Macrae Calum
Blakely , Sokoloff, Taylor & Zafman LLP
Maxim Integrated Products Inc.
Vo Tuyet Thi
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