Isolated power converter and associated switching power supply

摘要

In one embodiment, an isolated power converter can include: (i) a transformer having a primary winding and a secondary winding; (ii) a secondary rectifier circuit coupled to the secondary winding; (iii) a power switch coupled between an input voltage source and a first terminal of the primary winding, where a second terminal of the primary winding is coupled to ground; (iv) a feedback circuit coupled between the first and second terminals of the primary winding, the feedback circuit being configured to generate a feedback voltage based on a voltage across the primary winding; (v) a control circuit configured to generate a control signal to control the power switch; and (vi) an over voltage protection circuit configured to activate a reset signal when the voltage feedback signal is greater than a threshold value, where the reset signal is configured to reset the control signal when activated.

主权项

1. An isolated power converter, comprising:
a) a transformer having a primary winding and a secondary winding; b) a secondary rectifier circuit coupled to said secondary winding; c) a power switch coupled between an input voltage source and a first terminal of said primary winding, wherein a second terminal of said primary winding is coupled to ground; d) a feedback circuit coupled between said first and second terminals of said primary winding, and being configured to generate a voltage feedback signal based on a voltage across said primary winding; e) a control circuit configured to generate a control signal to control said power switch; and f) an over voltage protection circuit comprising a comparator configured to compare said voltage feedback signal against a threshold value, and to activate an over voltage signal when said voltage feedback signal is greater than said threshold value, and a logic circuit configured to activate a reset signal when said over voltage signal is activated outside of a predetermined time period, wherein said reset signal is configured to reset said control signal when activated.