ADAPTIVE LOOP GAIN CONTROL CIRCUIT FOR VOLTAGE CONTROLLED OSCILLATOR

摘要

PURPOSE: An adaptive loop gain control circuit for voltage controlled oscillator is provided to obtain a stable operational characteristic by compensating the oscillating control current and a gain of a PLL(Phase Locked Loop) according to a supply voltage and a variation of temperature. CONSTITUTION: An adaptive loop gain control circuit for voltage controlled oscillator includes a detection voltage generator(210) and a control circuit(220). The detection voltage generator(210) generates a detection voltage signal corresponding to a driving voltage and a variation of temperature. The control circuit(220) outputs an oscillation control current signal corresponding to the detection voltage signal and an input control voltage signal. The detection voltage generator(210) includes a noise filter in order to remove noise elements from the detection voltage signal. The noise filter is formed with a resistance and a capacitor.