ACCURATE RC OSCILLATOR HAVING PEAK-TO-PEAK VOLTAGE CONTROL

摘要

An RC oscillator circuit (10) within a microcontroller chip includes first and second comparators (16, 18) having their outputs respectively coupled to set and reset inputs of a flip-flop (20) whose output is coupled to a series RC network (22, 14) for controlling charging and discharging of a capacitor (14) of the RC network between precise high and low voltage levels (V2 and V1). One input of each comparator is coupled to the RC network, while the second input is coupled to a respective modified high and low threshold voltage level (Vh', V1'), so that the oscillator signal does not exceed the precise high and low voltage levels (V2, V1). The output frequency of the oscillator may be adjusted by selecting different values of the low voltage level (V1).