Patent ID: 9548666
Date: 2017-01-17
CPC Classifications: H02M

Claim:
1. A circuit for use in a switched mode power supply comprising: a switch; an integrated circuit including a switching signal generator operably coupled to the switch, the integrated circuit configured to jitter the frequency of the switch based on a voltage available at a bias voltage pin of the integrated circuit, the integrated circuit further comprising a current source coupled between a first terminal of the switch and a bias input pin, the current source configured to supply current for operation of the switching regulator when insufficient current is received through the bias input pin; a transformer comprising a primary winding, a secondary winding and an auxiliary winding, the primary winding operably coupled to receive a rectified line voltage, the primary winding further operably coupled to the first terminal of the switch; a capacitor coupled between the bias input pin and ground; a low voltage circuit operably coupled to the auxiliary winding, the low voltage circuit configured to provide voltage to the bias input pin; a current limiting resistor coupled between the low voltage circuit and the bias input pin, the current limiting resistor configured to limit current produced by the low voltage circuit to less than that required for operation of the integrated circuit.