| 摘要 |
PURPOSE:To eliminate the complete stop of an operation of a switching circuit except the defect of the switching circuit by providing a switching stop detector for monitoring the switching operation by producing part of switching waveform, and a feedback voltage regulator. CONSTITUTION:A voltage switched by a transistor 11 of a switching circuit 10 is output at 2 through a booster circuit 20 and a rectifying and smoothing circuit 30. The output 2 is fed back through voltage divider 40 to a comparator 50, the feedback voltage is compared with a reference voltage from a reference voltage source 60, the switching duty of the transistor 11 is controlled by a switching controller 70 to obtain a desired output 2. In this case, a switching stop detector 80 produces part of switching waveform, rectifies and smoothes it, and generate a positive DC voltage when the transistor 11 normally operates to connect a feedback voltage regulator 90 with the output of the divider 40. Thus, resistors 42, 92 are connected in parallel at voltage generation time, the feedback voltage reduced to extend the duty by the controller 70. |
