CMOS reference voltage source with adjustable output voltage

Abstract

The invention provides an output voltage adjustable CMOS reference voltage source to facilitate the realization of the standard CMOS process, which includes the start circuit, the positive temperature coefficient current generating circuit, the negative temperature coefficient current generating circuit, and the reference voltage generating circuit; the output of the start circuit connecting with the input of the positive temperature coefficient current generating circuit, the first output of the positive temperature coefficient current generating circuit respectively connecting with the first input of the negative temperature coefficient current generating circuit and the third input of the reference voltage generating circuit, the second output of the positive temperature coefficient current generating circuit respectively connecting with the second input of the negative temperature coefficient current generating circuit and the fourth input of the reference voltage generating circuit, the first and second outputs of the negative temperature coefficient current generating circuit respectively corresponding connecting with the first and second inputs of the reference voltage generating circuit, and the reference voltage generating circuit has the reference voltage output to output reference voltage.

Description

technical field [0001] The invention relates to a reference voltage source with low temperature coefficient and high power supply rejection ratio which needs to be generated in analog and digital-analog hybrid circuits, in particular to an adjustable output voltage CMOS reference voltage source. Background technique [0002] For analog circuits such as digital-to-analog converters, analog-to-digital converters, voltage converters, and voltage detection circuits, the voltage reference is a very important module. The stability of the reference voltage source is directly related to the working status and performance of the circuit. In order to meet the normal operation requirements of the circuit in different external environments, the voltage reference source should have the advantages of stable output, strong anti-interference ability, and small temperature coefficient. At present, the bandgap reference voltage source is commonly used, which is realized by a bipolar device, a...

AI Technical Summary

Problems solved by technology

However, there are many problems in the realization of the bandgap reference voltage source in the CMOS process, so its development is limited by many factors, and there are the following problems: due to the poor compatibility of bipolar devices in the CMOS process, amplifiers will be generated Therefore, the bandgap reference voltage source implemented on the CMOS process line will have problems such as whether the triode can be accurately and conveniently realized and how to reduce the amplifier offset

[0003] In addition, the output value of the commonly used bandgap reference voltage source is basically about 1.25V, which limits its application in some systems

Some application systems require a reference voltage value lower than 1V. The general bandgap reference voltage source cannot directly meet this requirement. It is necessary to design other voltage conversion circuits to reduce the output reference voltage value, which will also increase the difficulty of design.

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