SWITCHING REGULATOR WITH FAST TRANSIENT RESPONSE

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 (100,101) connected to the transformer secondary (19). The on time of said switches is controlled by a controller (14) to effect said regulation over a range of values of said 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 whilst said low voltage event persists.