| 摘要 |
PURPOSE:To reduce the loss of electric power at a series regulator by flowing a current from a DC/DC converter and the transformer of a switching regulator to the Zener diode of the series regulator. CONSTITUTION:The transformer T of a switching regulator 1 is provided with another winding n3; its one terminal is connected to the emitter of the transistor (TR)Q1 of a series regulator 2, and the other terminal is connected to a common point through the series circuit of a diode D1 and a capacitor C1. A current i2 flowing through a Zener diode ZD is one obtained by dividing a voltage, regulated by the Zener diode ZD, by a resistance R1, i.e., a current free from fluctuations of an input voltage VS. In addition, the value of the output voltage Vc(=Va+Vb) of a rectifying and smoothing circuit 3 may be greater than a Vz, so the Vs can rise up to a level higher than the Va approximately by the saturation voltage (about 0.2V) of the TRQ1, reducing the loss of a voltage at the series regulator 2 greatly. |
