| 摘要 |
PURPOSE: To provide a PLL circuit whose consumed power is small on standby. CONSTITUTION: The PLL circuit 250 has a PLL section 200, a signal change detection circuit 17 and a counter 20. The PLL section 200 generates internal clocks in synchronization with external clocks; the signal change detection circuit 17 detects whether external clocks are fed or not; the counter 20 counts internal clocks during the period when no external clocks are fed; and, when it counts a specified number, it stops oscillation of VCO installed in the PLL section 200. By this, since the oscillation of VCO in a specified period of time after the supply of external clock stops, power consumption on standby is reduced. |
