FREQUENCY STABILIZATION CIRCUIT OF RING OSCILLATOR

摘要

PURPOSE: A frequency stabilization circuit of a ring oscillator is provided to output a correct frequency by fully swinging an oscillation frequency between VCC and ground potential. CONSTITUTION: A control portion(10) receives a frequency selection signal(FS) and outputs control signals(Vcon,Vref) for controlling a delay oscillator portion(20) including a plurality of delay oscillators(20a-20n). The delay oscillator portion(20) is oscillated according to the control signal(Vcon) of the control portion(10). The delay oscillator portion(20) output a plurality of frequencies. A frequency output portion(30) receives frequencies outputted from the delay oscillator portion(20) and outputs final frequencies(F1-Fn) according to the frequency selection signal(FS). Each delay oscillator(20a-20n) of the delay oscillator portion(20) has a mirror portion and a buffer portion, respectively. The mirror portion is used for compensating a clock frequency. The buffer portion is used for buffering the compensated clock frequency.