Reverse biasing active snubber
View Patent ↗The present invention provides a transient suppression circuit for use with a rectifier coupled to a transformer. In one embodiment, the transient suppression circuit includes a triggering section configured to provide a timing signal corresponding to a dead time of the rectifier. Additionally, the transient suppression circuit also includes a biasing section coupled to the triggering section and configured to apply a reverse bias voltage to the rectifier based on the timing signal.
1. A transient suppression circuit for use with a rectifier coupled to a transformer, comprising:
a triggering section configured to provide a timing signal corresponding to a dead time of the rectifier; and
a biasing section coupled to the triggering section and configured to apply a reverse bias voltage to the rectifier based on the timing signal, wherein opposite ends of a secondary winding of the transformer provide connections for the timing signal and the rectifier, respectively.
2. The circuit of claim 1 wherein the timing signal corresponds to completion of a conduction time of a primary switch.
3. The circuit of claim 1 wherein applying the reverse bias voltage provides recovery of a reverse recovery condition of the rectifier.
4. The circuit of claim 1 wherein the reverse bias voltage is provided by a capacitor voltage.
5. The circuit of claim 4 wherein the capacitor voltage is developed during a non-conduction time of the rectifier.
6. The circuit of claim 1 wherein applying the reverse bias voltage employs a switch coupled to the timing signal.
7. The circuit of claim 1 wherein a pulse width modulation signal provides direct control of the timing signal.
8. The circuit of claim 1 wherein applying the reverse bias voltage to the rectifier provides a zero voltage switching condition for primary switches coupled to a primary winding of the transformer.
9. A method of operating a transient suppression circuit for use with a rectifier coupled to a transformer, comprising:
providing a timing signal corresponding to a dead time of the rectifier; and
applying a reverse bias voltage to the rectifier based on the timing signal, wherein opposite ends of a secondary winding of the transformer provide connections for the timing signal and the rectifier, respectively.
10. The method of claim 9 wherein the timing signal corresponds to completion of a conduction time of a primary switch.
11. The method of claim 9 wherein applying the reverse bias voltage provides recovery of a reverse recovery condition of the rectifier.
12. The method of claim 9 wherein the reverse bias voltage is provided by a capacitor voltage.
13. The method of claim 12 wherein the capacitor voltage is developed during a non-conduction time of the rectifier.
14. The method of claim 9 wherein applying the reverse bias voltage employs a switch coupled to the timing signal.
15. The method of claim 9 wherein a pulse width modulation signal provides direct control of the timing signal.
16. The method of claim 9 wherein applying the reverse bias voltage to the rectifier provides a zero voltage switching condition for primary switches coupled to a primary winding of the transformer.
17. A power converter, comprising:
a primary circuit having primary switches to couple a DC voltage source to a primary winding of a transformer;
a rectifier coupled between a secondary winding of the transformer and an output filter circuit; and
a transient suppression circuit coupled to the rectifier, including:
a triggering section that provides a timing signal corresponding to a dead time of the rectifier, and
a biasing section, coupled to the triggering section, that applies a reverse bias voltage to the rectifier based on the timing signal, wherein opposite ends of a secondary winding of the transformer provide connections for the timing signal and the rectifier, respectively.
18. The converter of claim 17 wherein the timing signal corresponds to completion of a conduction time of a primary switch.
19. The converter of claim 17 wherein applying the reverse bias voltage provides recovery of a reverse recovery condition of the rectifier.
20. The converter of claim 17 wherein the reverse bias voltage is provided by a capacitor voltage.
21. The converter of claim 20 wherein the capacitor voltage is developed during a non-conduction time of the rectifier.
22. The converter of claim 17 wherein applying the reverse bias voltage employs a switch coupled to the timing signal.
23. The converter of claim 17 wherein a pulse width modulation signal provides direct control of the timing signal.
24. The converter of claim 17 wherein applying the reverse bias voltage to the rectifier provides a zero voltage switching condition for primary switches coupled to a primary winding of the transformer.