| 摘要 |
PURPOSE:To secure the normal operation of a circuit to which a certain bias current is inputted, by constituting the device so that the certain bias current is generated independently of the variation of a load. CONSTITUTION:When a power switch SW1 is turned off, a control circuit 10, an operating circuit 4, and a follower 7 are not fed, and these circuits are not operated. However, a current is flowed to transistors TRs 20 and 21 from a power source E to bias an oscillating circuit 22. The oscillating operation is held by this bias current, and therefore, the operation delay of the oscilltor for turning- off of the power switch is eliminated. Next, when the switch SW1 is turned on, the circuit 10 is operated, and a feed control signal VP is applied to the circuit 4 and the follower 7 to operate these circuits. Consequently, the follower 7 applies a certain voltage VS with a power source voltage VCC as a reference to the connection point between resistances 19 and 9. Consequently, the bias current flowed to TRs 20 and 21 becomes a certain value independent of the voltage VCC. Therefore, the oscillator outputs a certain frequency. |
