US 9,812,976 B2
Control of a startup circuit using a feedback pin of a PWM controller integrated circuit chip
Hangseok Choi, Bedford, NH (US)
Assigned to Fairchild Semiconductor Corporation, San Jose, CA (US)
Filed by FAIRCHILD SEMICONDUCTOR CORPORATION, San Jose, CA (US)
Filed on May 2, 2016, as Appl. No. 15/144,316.
Claims priority of provisional application 62/186,681, filed on Jun. 30, 2015.
Prior Publication US 2017/0005583 A1, Jan. 5, 2017
Int. Cl. H02M 1/36 (2007.01); H02M 3/335 (2006.01); H02M 1/00 (2006.01)
CPC H02M 3/33553 (2013.01) [H02M 1/36 (2013.01); H02M 2001/0006 (2013.01); H02M 2001/0009 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An integrated circuit (IC) chip comprising:
a gate pin that is configured to output a control signal for driving a control transistor of a switching mode power supply;
a current sense pin that is configured to receive a current sense signal indicative of a current through the control transistor;
a feedback pin that is configured to receive a feedback signal that is indicative of an output voltage of the switching mode power supply and is configured to be connected to a control terminal of a high voltage (HV) startup transistor that is external to the IC chip;
a startup control circuit that is configured to drive the control terminal of the HV startup transistor from the feedback pin; and
a pulse width modulator that is configured to generate the control signal that is output at the gate pin to regulate the output voltage by pulse width modulation (PWM) based on the feedback signal received on the feedback pin and the current sense signal received on the current sense pin.