Patent ID: 8824172

Claim:
An apparatus for standby power reduction of a flyback power converter including a capacitor connected between an output and a ground for supplying a load current and an output feedback circuit for output feedback, the apparatus comprising: a shunt regulator connected to the output feedback circuit, operative to provide a reference voltage; a voltage divider connected to the output and the shunt regulator, for determining an output voltage at the output of the flyback power converter according to a voltage dividing ratio of the voltage divider; a switch-resistor network connected in parallel to a resistor in the voltage divider, including a switch controlled by a sleep mode signal to switch the voltage dividing ratio; a current sense resistor in a current path of the load current to generate a current sense voltage; and a comparator connected to the current sense resistor, comparing the current sense voltage with a threshold value to assert the sleep mode signal.