| 摘要 |
PURPOSE:To stabilize an output voltage except a main output by controlling ON or OFF of a switch circuit so that the lowest DC voltage of rectifying and smoothing circuits becomes constant. CONSTITUTION:AC voltages obtained in the secondary windings n2, n3 of a transformer T1 are smoothed by diodes D1-D4, coils L1, L2 and capacitors C1, C2, and output voltages V01, V02 are output. A comparator U1 inputs the lowest DC output voltage V01 of rectifying and smoothing circuits, compares the voltage V01 with a reference voltage Vr, and controls ON or OFF a switching transistor Q1 through a pulse width modulator 1 and a drive circuit 2.
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