Switched power supply - generates negative pulses that are rectified to produce negative constant voltage

摘要

A switched power supply circuit is used to generate a negative bias voltage (-U) for use in a TV or video recorder. The positive input voltage (+Vcc) to a transistor (Ts) and coil (L) via a filter that is in the form of resistance (1) and capacitor (2). The transistor (Ts) is operated at 30 kHz by an applied input (Us). By switching off the transistor, a pulse (3) is generated which is rectified by a diode (D) and a capacitor (4) to produce the constant negative voltage (-Uv). ADVANTAGE - Simple circuit to generate negative voltage.