Patent ID: 8000116

Claim:
An output protection circuit used for a power converter comprising: an operational amplifier; a diode; a plurality of voltage-dividing resistors; and a switch tube; wherein the voltage-dividing resistors R 3 and R 4 are connected in series to form a voltage-dividing network, wherein one node of the network is connected to a reference level end Vref of a PWM control module of the converter, while the other node is grounded; a voltage dividing point M is coupled to an inverting input end of the operational amplifier AR 1 ; the voltage dividing resistors R 1 and R 2 are connected with each other such that a voltage dividing network is defined, wherein one node of the network is coupled to a compensation level end Comp of said PWM control module via the diode D with a inversed configuration, while the other node is grounded; One node of a voltage point N is connected with a non-inverting input end of the operational amplifier AR 1 , while the other node is connected to an output end of the operational amplifier AR 1 through a capacitor C 1 ; An inverting input end of the operational amplifier AR 1 is coupled to a reference level end Vref of the PWM control module, and the output end thereof is connected to the switch diode via the resistor R 5 and then go back to the compensation level end Comp.