| 摘要 |
A power converter for delivering power to a load at a regulated voltage 11 includes a regulating stage receiving an unregulated supply 10 and having a main transformer 18. Switches 16a and 16b are arranged in a half-bridge connect the transformer primary 17 to the unregulated supply 10 to drive the load via a rectifying stage connected to the transformer secondary 19. The on-time of the switch is controlled by a controller 14 to effect the regulation over a range of values of the unregulated supply. An auxiliary transformer 103 has a secondary winding 104 connected in series with the main transformer primary 17 and a primary winding that is selectively driven via a switch 106. A comparator 107 detects a low voltage event within the regulating stage, such as a drop in the intermediate voltage at 10. The primary winding 105 of the auxiliary transformer 103 is driven during the low voltage event. |
