| 摘要 |
PURPOSE:To control the duty ratio of an oscillated signal to take a specific value by comparing the duty ratio of the output signal of an oscillation circuit with a specific value by a duty detecting circuit, and changing modes of feedback according to their difference. CONSTITUTION:The output of the duty detecting circuit 22 is led out of TRs T31 and T32 through their sources as V1 and V2, which are inputted to a differential amplifier 23. When the duty ratio of the output signal of the oscillation circuit is greater than a specific value 1/n determined by threshold values of TRs T31, T32, and T34 constituting the duty detecting circuit 22, V2<V1, so the potential at a point (e) drops to increase the resistance value of an N channel TR and the discharge time of the oscillation circuit is prolonged to provide such feedback that the duty ratio is increased. On the other hand, when the duty ratio of the output signal of the oscillation circuit is less than the specific value 1/n, V2>V1, so the potential at the point (e) rises to decrease the resistance value of a TRTf, providing such feedback that the duty ratio is increased. |
