| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce a reference leak and phase noise of a PLL circuit. <P>SOLUTION: A charge pump circuit 14 switches a charge pump current on the basis of a signal outputted from a locked-state monitoring circuit 19 to indicate whether or not a PLL circuit 11 is in a locked state. When the PLL circuit 11 is in an unlocked state, the charge pump current is supplied from first/second current supply circuits. When the PLL circuit is in the locked state, the charge pump current is supplied only from the second current supply circuit. <P>COPYRIGHT: (C)2010,JPO&INPIT |
