| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a semiconductor integrated circuit device provided with a PLL circuit having a reliable deadlock unlocking function. <P>SOLUTION: In a deadlock unlocking circuit for the PLL circuit, a control voltage monitor circuit detects a state that VCO control voltage corresponding to the phase comparing output of the PLL circuit exceeds a regulated value, a phase monitor circuit detects a state that a reference signal and a feedback signal are deviated by an input half cycle or more, and a judgment circuit judges a dead lock state only when both of the detection signals of the control voltage monitor circuit and the phase monitor circuit are established to unlock the deadlock state by forcedly dropping the VCO control voltage. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
