Ac inverter capable of driving mutliple lamps for lcd panel backlight
AssigneeWestinghouse Digital Electronics, LLC
InventorsHing S. Tong, Shi Kuang Tan
Life of this patent
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Abstract
An AC inverter circuit supplies power to multiple lamps in an LCD backlight. Conventional AC power is used as direct input into a full wave rectifier that converts the input from AC to a DC reference voltage. A transformer driver, including a chopper, converts the DC reference voltage to a higher voltage AC which drives a step up transformer to produce a voltage sufficient to drive as many as six fluorescent lamps. The components/circuitry associated with the transformer's primary windings is optically isolated from the rest of the circuit.
Claims18
An AC inverter circuit that supplies power to multiple lamps in an LCD backlight comprising:
- (a) a full wave rectifier, for converting direct input AC current into a reference voltage;
- (b) a transformer driver, wired to said full wave rectifier, that converts said reference voltage into an AC current;
- (c) a step up transformer, wired to said transformer driver, for increasing the voltage of said AC current to a high voltage AC current;
- and
- (d) at least two lamps, serially wired to said step up transformer, that are actuated by said high voltage AC current.
A circuit that controls illumination of lamps illuminating a flat panel display, comprising:
- (a) at least two lamps connected in series;
- (b) a current monitor, connected to said at least two lamps, for detecting the current flowing through said series;
- (c) a driver controller, connected to said current monitor, for receiving feedback from said current monitor;
- and
- (d) a transformer controller, connected to said driver controller, for controlling a transformer.
A circuit that supplies standby power to a full wave rectifier, comprising:
- (a) a source of AC power generating an AC current;
- (b) a standby power supply, connected to said source of AC power, for converting said AC current into a standby Vdc current;
- (c) a remote sensor logic, connected to said standby power supply, to receive said standby Vdc;
- (d) an AC power switch, connected to said remote sensor logic and said source of AC power, wherein said remote sensor logic receives signals from a remote source and generates a “power on” signal that is sent to said AC power switch, which upon reception of said “power on” signal, sends a switched voltage to the full wave rectifier.
A semiconductor system that uses digital wave shaping to create a desired output signal to control a light, comprising:
- (a) a source of AC current;
- (b) digital wave shaping circuitry, connected to said source of AC current;
- and
- (c) a series of fluorescent lamps, connected to said digital wave shaping circuitry, for illuminating an area.
A system that converts AC voltage to appropriate power levels for driving multiple serially connected lamps, comprising, at least the following elements:
- (a) a full wave rectifier;
- and
- (b) at least two lamps, wired in series, connected to said full wave rectifier.
A system that provides optimal initial startup voltage and current in order to extend the useful life of fluorescent lamps in a flat panel television, comprising:
- (a) a series of fluorescent lamps;
- (b) a standby circuit, connected to said lamps, for storing the optimal initial startup voltage for immediate delivery;
- and
- (c) a control mechanism, connected to said standby circuit, whereby said standby circuit may be activated.
A system that reduces wire use and the volume of high voltage signals within a television, comprising:
- (a) a full wave rectifier;
- (b) at least two serially connected lamps, and
- (c) wire sufficient to connect the first of said at least two lamps to said full wave rectifier.
Dependencies are inferred from the claim text.