| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply device of a forward-coupling converter type that is used to a lighting power supply device or the like, to surely achieve reductions of ripple rate of DC load current and noise, facilitated in the constitution of the device as a circuit constitution, and that further can perform higher frequency switching. SOLUTION: The FCC-type power supply device is configured, such that an AC input is rectified and inputted to a primary winding of a transformer, and a DC driven lamp load is connected to a secondary winding of the transformer via a smoothing and rectifying circuit. The circuit configuration comprises an operational amplifier that amplifies the voltage drop amount generated from a current flowing to a detection resistor, by connecting the DC driven lamp load to the detection resistor in series, and a pulse-width control device circuit, that is optically coupled to the operation amplifier and controls the pulse width of the primary winding of the transformer by switching an FET element. COPYRIGHT: (C)2005,JPO&NCIPI
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