| 摘要 |
PROBLEM TO BE SOLVED: To correct temperature change of a resistance component of a choke coil, in a current detection circuit for detecting current flowing in the choke coil using the resistance component of the choke coil. SOLUTION: The current detection circuit includes a series circuit of a resistor R2 and a capacitor C2 connected in parallel to the choke coil L1 of a smoothing circuit for supplying, to a load via the smoothing circuit, an output signal switched by an switching elements Q1 such as a field-effect transistor, a differential amplifier OP1 to input the voltage of both ends of the capacitor C2 of the series circuit, and resistors R5, R6 and R7 and a temperature-sensitive resistance element Rt for applying an output signal V1 of the differential amplifier OP1. The current detection circuit sets, as a current detection signal, the voltage divided by the resistors R5, R6 and R7 and the heat-sensitive resistance element Rt. COPYRIGHT: (C)2009,JPO&INPIT
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