Patent ID: 7257008

Claim:
A start-up apparatus for starting up a power converter, which is supplied with an input voltage and is connected to a holding capacitor, comprising: a transistor, having a source, a gate and a drain, said drain of said transistor is supplied with said input voltage, said source of said transistor being connected to said holding capacitor; a start-up control unit, having an input and an output, said input of said start-up control unit being connected to said holding capacitor and said source of said transistor, said output of said start-up control unit being connected to said gate of said transistor; and a switch, connected to said output of said start-up control unit and said holding capacitor, wherein said input voltage drives said transistor on and charges said holding capacitor, wherein said start-up control unit draws a start-up voltage from said holding capacitor to drive on said switch and to provide a voltage across said holding capacitor for a control circuit, wherein said start-up control unit also turns off said transistor to cut off a charging path from said input voltage to said holding capacitor.