Switched capacitor clock generator

Abstract

The invention relates to a switched capacitor clock generator that comprises an adjustable voltage generation circuit, a switched capacitor circuit, an integrator, a sampling hold circuit, a voltage controlled oscillator, a frequency divider and a bias generation circuit. The adjustable voltage generation circuit and the switched capacitor circuit are respectively connected with input terminals of the integrator, and the adjustable voltage generation circuit generates a voltage that is used for controlling a center frequency of the voltage controlled oscillator; the switched capacitor circuit generates discontinuous currents; the integrator generates a sawtooth wave output voltage and the output terminal of the integrator is connected with the sampling hold circuit; an output terminal of the sampling hold circuit is connected with the voltage controlled oscillator and the sampling hold circuit is used for providing a control signal for the voltage controlled oscillator; and the voltage controlled oscillator generates a frequency signal and the output terminal of the voltage controlled oscillator is connected with the frequency divider. According to the invention, the structure of the generator is simple; a clock signal with high precision can be generated; and the temperature characteristic, the technology stability and the power supply inhibition capability of the provided generator are better than those of an existing clock generator.

Description

technical field [0001] The invention relates to a clock generator, in particular to a switched capacitor clock generator based on CMOS technology. Background technique [0002] In various electronic systems, the clock signal is an indispensable reference signal. It has a wide range of applications from clock generation in microprocessors to carrier synthesis in cellular phones, as well as measurement, remote control and automatic control. Usually, the clock signal in the electronic system generates a reference clock signal through a quartz crystal oscillator set outside the electronic system, and then the phase-locked loop in the system outputs a higher frequency clock signal for the internal circuit based on the reference clock signal. use. However, although a more accurate clock signal can be generated by using a quartz crystal oscillator to generate a clock signal, this method requires pins to receive the reference clock signal, which will cost a higher pin cost. [000...

AI Technical Summary

Problems solved by technology

The RC oscillator has a simple structure and is easy to implement, but its accuracy is poor, and it varies greatly with temperature and power supply voltage. It is generally used in occasions that do not require high clock accuracy.

In order to obtain better precision, the oscillator adopts a ring structure, which is usually composed of several delay circuits with a certain gain in a closed-loop form, but the disadvantage of this type of oscillator is that the circuit is more complicated, and the temperature characteristics, process stability and power supply Inhibition is also poor

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