PURPOSE: To improve the input power factor and suppress the increase of the switching loss and the power loss of a control circuit.
CONSTITUTION: A chopper circuit 1 outputs the DC boosted from the output of a rectifier DB to drive an inverter circuit IV, and a discharge lamp La is lighted by the high-frequency power outputted from the inverter circuit IV. The switching element Q1 of the chopper circuit 1 is turned on or off by a control circuit 2. The control circuit 2 is provided with the first control circuit 2a changing the operating frequency of the switching element Q1 in response to the input/output of the chopper circuit 1 and the second control circuit 2b turning the switching element Q1 on or off with the constant operating frequency. A selecting circuit 3 operates the switching element Q1 with the first control circuit 2a when the power consumption of a load circuit Z is large and operates the switching element Q1 with the second control circuit 2b when the power consumption of the load circuit Z is small.
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| JP4063625 | Discharge lamp lighting device |
NISHIURA KOJI
HAMAMOTO KATSUNOBU
YAMANAKA MASAHIRO
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