Switching regulator for producing DC voltage from low input voltage - has switching transistor controlled from first pole of DC voltage across resistance connected in prim. circuit of transformer

摘要

In the switching regulator, a resistance (4) is provided, one end of which is connected to the emitter circuit of the switching transistor (1) and the other end is connected to the second pole of the input voltage. The prim. winding (2) of the transformer is arranged connected at one end to the first pole of the input voltage and at the other end to the collector circuit of the switching transistor (1). The sec. winding (6) of the transformer is connected to a rectifier stage (7) without galvanic separation to the input voltage. A series circuit consisting of diodes (10,11) antiparallel to each other and also a Z diode (12) is arranged in series to the sec. winding (6) of the transformer against the second pole of the input voltage (5). The junction point between the connection of the sec. winding (6) and the antiparallel diodes (10,11) makes contact with the base of the switching transistor (1). USE/ADVANTAGE - Switching regulator for producing DC voltage from comparatively low input voltage. Gives selective and low loss switching on and off characteristics independent of load conditions of output circuit. Esp. without auxiliary transformer winding or separate excitation for transistor and without protective elements for transistor. Powering flash unit for camera, gas laser or similar requiring h.v. for firing of several hundred volts from l.v. source, e.g. battery, on-board power network.