| 摘要 |
PURPOSE:To remove deviation between the direct current component of the output of a phase comparator and reference voltage by generating the reference voltage by a reference voltage generation circuit by using the positive-phase output and the negative-phase output of a phase comparator, and supplying this reference voltage to a loop filter as bias voltage. CONSTITUTION:The phase comparator 40 is constituted of a bipolar ExOR to compare the phases of an input signal with a feedback signal and send the positive-phase output and the negative-phase output corresponding to this compared result. The reference voltage generation circuit 50 generates the reference voltage of a prescribed level based on the positive-phase output and the negative-phase output, and supplies this reference voltage to the loop filter 60. The phase comparator 40 of bipolar constitution enables high-speed operation, and the reference voltage generation circuit 50 generates the reference voltage corresponding to the change of the direct current component of the output of the phase comparator 40, and supplies this reference voltage to the loop filter 60 as the bias voltage. Thus, the deviation between the direct current component of the output of the phase comparator 40 and the reference voltage is eliminated. |
