A trimming circuit for oscillator and its trimming method

Abstract

The invention provides a tuning method of a high accuracy resistance capacitance oscillator. The tuning method is achieved through three tuning of tuning of an input voltage V1, tuning of a voltage reference (VREF) and tuning of a reference current input reference (IREF). One stage of the three stage tuning is coarse tuning, another is medium tuning, and the rest is fine tuning according to different positions of a switch. The output frequency of the oscillator achieves the designed accuracy through the three stage tuning. According to the tuning method, the tuning of the reference current IREF is achieved by adjusting voltage at two ends of the whole resistor series; and the matching of the limited number of resistors is relatively easy to achieve, and higher accuracy tuning can be achieved.

Description

technical field [0001] The invention relates to integrated circuit oscillator technology, more specifically, to a trimming circuit and trimming method for a high-precision resistor-capacitor oscillator. Background technique [0002] High-precision clock generator is the main module of digital-analog hybrid integrated circuit and digital integrated circuit. A crystal oscillator can provide a stable clock independent of process, power supply voltage and temperature, but it is not compatible with integrated circuit process and has a relatively high cost, so its application is limited. With the development of CMOS integrated circuit technology and SOC technology, more and more clock generators are realized by CMOS circuits. [0003] The RC Oscillator is a common oscillator type that can be implemented in standard CMOS processes. It can be used as a clock generator to generate the required clock frequency. There are many different types of RC oscillators, such as relaxation os...

AI Technical Summary

Problems solved by technology

[0009] figure 2 and image 3 The trimming method shown has some disadvantages: First, if higher accuracy is desired, a higher number of switches is required, which takes up more chip area

At the same time, more switches will increase the complexity of the logic control part; secondly, the switch itself has an on-resistance, which will adversely affect the accuracy of the oscillator

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