| 摘要 |
PURPOSE:To prevent transient voltage variation from being caused by switching a source voltage and a constant voltage by the reference voltage generation part of a constant voltage control loop. CONSTITUTION:The P channel FET 4 of a constant voltage circuit which includes an oscillation circuit as a load is off until a switching signal is outputted from a switching signal input terminal 6 and the uninverted input side of an operational amplifier 2 is led to the power source terminal side of the current source for the N channel FET 12 of the reference voltage generation part 1 of the constant voltage control loop. Therefore, when the FET 4 turns on which the switching signal from the terminal 6, a current path to the power source is formed to generate a reference voltage, and the source voltage and constant voltage are switched not only the feedback side of the amplifier 2, but on the reference voltage side of the constant voltage control loop. Therefore, the constant voltage is prevented from having transient variation and the timepiece which uses only a solar battery varying in voltage frequently operates stably. |
