PHASE COMPARATOR AND PHASE LOCKED LOOP

摘要

PROBLEM TO BE SOLVED: To stabilize the output voltage of a phase comparator in a region where a phase difference of an input signal is very small and to stabilize the closed loop of a phase-locked loop, using the phase comparator in a region where a phase difference of an input signal is very small. SOLUTION: This comparator is provided with a phase comparator section 21 that generates a lead signal A and a lag signal B and signal amplifier circuits 23, 25 that receive the lead signal A and the lag signal B, and the signal amplifier circuits 23, 25 are respectively composed of a P-channel MOS TR 31, a 1st load circuit 32 at a P-channel side, an N-channel MOS TR 33, and a 2nd load circuit 34 at an N-channel side. In this case, let a load of the 1st load circuit 32 of the signal amplifier circuits 23, 25 be L1 and let a load of the 2nd load circuit 34 be 2, then a relation L1L2 is established in the signal amplifier circuit 25.