| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a circuit for controlling a switching power supply, and a switching power supply wherein a circuit failure can be accurately detected. SOLUTION: A feedback voltage Vfb1 (Vfb2) corresponding to the output voltage Vout1 (Vout2) of each channel is input to a corresponding feedback terminal P1 (P2). A corresponding error amplifier 10 (20) outputs a voltage Verr1 (Verr2) corresponding to the difference between the voltage Vfb1 (Vfb2) of the corresponding feedback terminal P1 (P2) and a corresponding predetermined reference voltage Vref1 (Vref2). A corresponding pulse width modulator 11 (21) outputs a pulse signal Vpwm1 (Vpwm2) whose duty ratio varies according to the corresponding error voltage Verr1 (Verr2). A corresponding driver circuit 16 (26) drives a switching element based on a pulse signal. A corresponding monitor circuit 30 (40) monitors at least either error voltage Verr. When the value of this voltage gets out of a predetermined range, the monitor circuit stops driving of the switching element on at least one channel. COPYRIGHT: (C)2008,JPO&INPIT
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