| 摘要 |
PURPOSE:To eliminate a problem of the level conversion by using a power supply different from those of other circuits to a phase comparator of a PLL circuit formed on a semiconductor substrate. CONSTITUTION:The component parts including a charge pump 8 are formed on a single chip, and the voltage is supplied to a phase comparator 5 and the pump 8 via power terminal 21. Meanwhile the voltage is supplied to a reference divider 1 and a programmable counter 2 via a power terminal 20. Thus at least the divider 1 and the counter 2 are actuated with the voltage of a low level in a PLL circuit formed on a semiconductor substrate. As a result, the current consumption is reduced and furthermore a problem of the level conversion can be eliminated since the different power source supplies power to the comparator 5 and the subsequent component parts. |
