| 摘要 |
A standby mode switching circuit of a switching power is disclosed. The standby mode switching circuit having a bias controller(R1), a transistor(Q1) for operating a transformer(T1), a voltage sensor(1) for sensing the voltage discharging from the transformer(T1), a current controller(2) for controlling the current of the base of the transistor(Q1); a constant current provider(3) for proving a constant current to the transformer(T1), an excess voltage prevention unit(4), a diode(D4) and a capacitor(C5), further comprises: a transistor(Q5) for receiving a DPM(Display Power Management) signal and for operating an ON/OFF operation, a photo coupler(PC1) for operating the standby mode controller(5) in case of switching "ON"; and a relay(R11), responsive to the control signal from the standby mode controller(5), for maintaining a low switching frequency in case of a low load.
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