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US 2008/0185979 A1Published application
Discharge Lamp Drive Control Circuit
AssigneeSumida Corporation
InventorHiroyuki Miyazaki
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AssigneeSumida Corporation
InventorHiroyuki Miyazaki
Estimating the term…
A single comparison circuit detects load open circuit abnormality and load short circuit abnormality of a discharge lamp operating at a high-frequency driving voltage, with a small number of circuit elements. A discharge lamp drive control circuit includes an inverter control circuit, a positive change voltage detecting circuit which detects a positive change of voltage occurring in the secondary coil of a driving transformer, a negative change voltage detecting circuit which detects a negative change of voltage occurring in the secondary coil of the driving transformer, and the comparison circuit connected to the inverter control circuit. The outputs from the positive and negative change voltage detecting circuits are added to generate an added output, and the added output is supplied to the comparison circuit and compared with a reference voltage. When an abnormal operation occurs, the comparison circuit supplies an abnormal operation control signal to the inverter control circuit.
A discharge lamp drive control circuit which turns on a discharge lamp by applying, to the discharge lamp, a high-frequency driving voltage generated in a secondary coil of a driving transformer comprised in an inverter, comprising:
A multi-lamp-type discharge lamp drive control circuit which has a plurality of driving transformers comprised in an inverter, and turns on discharge lamps by applying, to the discharge lamps, high-frequency driving voltages generated in secondary coils of said driving transformers, comprising:
Dependencies are inferred from the claim text.