Patent ID: 8698474
Filing Date: 2014-04-15
Classification: H02M

Abstract:
1. A start-up circuit for a power converter, comprising: a first diode coupled to an input voltage of the power converter; a second diode coupled to the input voltage of the power converter and the first diode; a start-up resistor coupled to the join of the first diode and the second diode; a high-voltage switch coupled to the start-up resistor and utilized to generate a power source; a control circuit generating a switching signal for switching a transformer; and a detection circuit coupled to the high-voltage switch to generate a disable signal in response to the input voltage of the power converter; wherein a power supply of the control circuit is supplied by the power source, a winding of the transformer is further coupled to the power source to generate a power for the power source; the high-voltage switch is turned off and stopped generating the power source once the voltage of the power source is higher than a threshold; the high-voltage switch is turned on once the voltage of the power source is lower than the threshold; the switching signal is disabled in response to the disable signal.