Method and circuitry for controlling current reset characteristics of a magnetic amplifier control circuit

摘要

Magnetic amplifier post regulator (54) includes magnetic amplifier (42) that has a main magnetic amplifier winding, reset transistor (76), error amplifier (58), and auxiliary magnetic amplifier winding (220). Magnetic amplifier (42) controllably blocks a portion of the input voltage Ns/Np VIN from winding (30) of transformer (18) in response to a controlled resetting condition and produces therefrom a magnetic amplifier output voltage (v2). Auxiliary output circuit (14) uses the magnetic amplifier (42) output voltage (v2) to produce the desired auxiliary output voltage (VOS). Reset transistor (76) controls reset current to magnetic amplifier (42) in response to an error signal from error amplifier (58). Error amplifier (58) compares auxiliary output voltage (VOS) to predetermined reference voltage (66) and generates the error signal from the comparison. Auxiliary magnetic amplifier winding (220) has a predetermined number of turns (N2) on magnetic amplifier (42) and increases the dynamic range of magnetic amplifier post regulator (54) for controlling reset transistor (76) and auxiliary output circuit (14) so that auxiliary output voltage (VOS) may attain a zero value while reset transistor (76) controls magnetic amplifier (42) in a blocking state (TB) during the entire on-time (TON) of power switch transistor (24) of primary circuit (16).