Mains connection part for operation voltage stability - has transformer,secondary winding arranged across diode and delivering current to chargingcapacitor

摘要

A regulating voltage (Ur) for controlling the switched ON duration of a switching transistor (T1) on the prim. side of the transformer (Tr), depending on the sec. side operating voltage (U5), is obtained. A transistor (T2) is arranged parallel to the diode (D1), which after the dying away of the charging current (ID), is controlled conducting depending on the operating voltage (U5) during a fraction of the switched ON duration of the switching transistor (T1). A regeneration current (iT2) flows opposite to the charging current (iD) so that energy from the charging capacitor (4) is returned to the transformer (Tr). The regulating voltage (Ur) on the prim. side is obtained from the voltage (U2) induced by the regeneration current (iT2). The transistor (T2) is controlled by a comparator (V), in which the operating voltage (U5) is compared with a reference voltage (Ref). USE/ADVANTAGE - Mains connection part, which stabilises operating voltage by regulating switching transistor on prim. side. Technically simple manner without additional switches allows transmission of regulating data from secondary to primary side of transformer still maintaining galvanic separation.