| 摘要 |
PURPOSE:To reduce the change in an oscillating frequency at a wide power supply voltage range and to decrease the oscillation start time by using a constant current circuit to drive an oscillation circuit and a frequency divider circuit frequency-dividing the output of the oscillation circuit. CONSTITUTION:The oscillation circuit 1 and the frequency division circuit 2 are driven by constant current circuit 4. Moreover, an output signal is obtained by using the frequency divider circuit 3. On the other hand, a control circuit 7 is a control circuit turning on a switch circuit 6 after application of power and generating a signal turning it off after a prescribed time is elapsed. The level of a signal 7c goes from a high to a low level after application of power, a one-shot pulse 7b is generated, it brings a signal 3c into a low level, an RS latch circuit is set and an MOS transistor (Tr) 9 is turned on. Thus, the constant current circuit 4 is inactuated, a power supply voltage is applied to the oscillation circuit 1 and the frequency division circuit 2 to start the oscillation. The signal 3a goes to a high level after a prescribed time by the frequency divider circuits 2, 3, the MOS Tr9 is turned off and then a power is applied from the constant current circuit 4. |
