| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply device capable of achieving improvement of efficiency during light load without causing an increase in an output ripple voltage, and an electric apparatus equipped therewith. SOLUTION: The power supply device has a configuration having a transformer 1; oscillation transistor Tr2 serially connected to a winding Np; activation circuit 3 for utilizing an input voltage Vi and an induction voltage Vd to turn on the Tr2; oscillation control transistor Tr4 for turning off the Tr2 by turning-on of itself; stopping circuit 5 for utilizing the Vd to turn on/off the Tr4; output smoothing circuit 6 for smoothing an induction voltage Vs to generate an output voltage Vo; output detecting circuit 7 for detecting whether or not the Vo reaches a threshold; and stop control circuit 8 for utilizing the Vd to expedite an on-timing of the Tr4, if the Vo has reached the threshold during the off period of the Tr4, and delaying the off timing of the Tr4 until the forcible on-period elapses or the Vo becomes lower than the threshold earlier than that, if the Vo has reached the threshold during the on-period of the Tr4. COPYRIGHT: (C)2008,JPO&INPIT
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