INJECTION-LOCKED FREQUENCY DIVIDER AND PLL CIRCUIT

摘要

Disclosed are a PLL circuit and an injection-locked frequency divider that can lessen the effect of parasitic capacitance and wherein the operating frequency is broadband. The injection-locked frequency divider (100) is provided with: a first amplification circuit (141) configured from an N-channel MOS transistor (111) and a P-channel MOS transistor (112); a ring oscillator (140) wherein a second amplification circuit (142) and a third amplification circuit (143) having a similar configuration have a ring-shaped three-stage cascade connection; an N-channel MOS transistor (150) wherein the source of the N-channel MOS transistor (111, 121, 131) of each stage is connected to the drain thereof; and a differential signal injection circuit (160) that injects an injection signal (I1) to the gate of the P-channel MOS transistor (112, 122, 132) of each stage and that injects a reversed-phase signal of the injection signal (I1) as a differential signal to the gate of the N-channel MOS transistor (150).