Resistance capacitance (RC) oscillator with low power consumption

Abstract

The invention provides a resistance capacitance (RC) oscillator with low power consumption, which can generate clock control signals with a duty ratio of which the accuracy is increased required by an internal circuit. The RC oscillator comprises a bias circuit, a first inverter, a second n-channel metal oxide semiconductor (NMOS) transistor, a first capacitor, a second inverter, a third NMOS transistor, a second capacitor, a third inverter, a fourth inverter, a fifth inverter, a sixth inverter, an RS trigger, a nor gate and a fourth NMOS transistor, wherein the bias circuit comprises a resister and a first NMOS transistor; a first input end and a second input end of the RS trigger are respectively connected with a first input end and a second input end of the nor gate; the output end of the nor gate is connected with a grid electrode of the fourth NMOS transistor; a first output end of the RS trigger is connected with a drain electrode of the fourth NMOS transistor; and the source electrode of the fourth NMOS transistor is grounded.

Description

technical field [0001] The invention relates to an oscillator in a CMOS integrated circuit, in particular to an RC oscillator with low power consumption, which can generate a clock control signal with improved duty cycle precision required by an internal circuit. Background technique [0002] Commonly used oscillators are generally divided into three types: RC oscillators (ie, resistance-capacitance oscillators), ring oscillators, and crystal oscillators. The RC oscillator has the advantages of short start-up time, easy frequency adjustment, and easy design and manufacture using common CMOS integrated circuit technology. [0003] figure 1 and figure 2 A schematic diagram of a prior art RC oscillator is shown. [0004] Such as figure 1 and figure 2 As shown, the RC oscillator includes a bias circuit, two comparators COMP1 and COMP2, an RS flip-flop and some digital logic. [0005] The bias circuit in the RC oscillator includes a resistor R and a diode-connected NMOS t...

AI Technical Summary

Problems solved by technology

[0030] Second, due to the different parasitic capacitances at the two nodes FEED and FEEDB, the duty cycle performance of the RC oscillator is degraded

[0031] Third, in this RC oscillator, an inverter is inserted between the nodes FEED and FEEDB, then there is an inverter delay between these two signals, which changes the original completely symmetrical circuit, and also makes the occupied Duty down

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