Low voltage CMOS current source

Abstract

The invention discloses a low voltage CMOS current source, and belongs to the field of analog integrated circuit. The low voltage CMOS current source comprises a PTAT voltage source, a current converting circuit and a mirror image circuit which are connected with the PTAT voltage source, wherein, the PTAT voltage source is used for generating a reference voltage V[REF] with a positive temperature coefficient; and the current converting circuit and the mirror image circuit are used for converting the reference voltage V[REF] into a reference current, and outputting the reference current by a current mirror relation. The low voltage CMOS current source has good power supply property and temperature property, and process deviation of the CMOS current source has little influence on an output current value of the CMOS current source.

Description

Technical field [0001] The invention relates to the field of analog integrated circuits, in particular to a low-voltage and high-precision CMOS current source. Background technique [0002] As a key circuit unit of analog integrated circuits, current sources are widely used in the design of mixed-signal integrated circuits such as A / D (analog / digital) converters, D / A converters and Viterbi decoders. [0003] At present, the commonly used current source design method is based on the bandgap voltage reference source to generate the reference current at both ends of the reference resistor, but the process error of the integrated reference resistor is very large, such as the 0.6μm CMOS Poly2 resistor PCM parameter is 800±150 ohms per square , The reference current value and temperature coefficient cannot be guaranteed; and if an external reference resistor is used, it will not only increase the cost, but also cannot guarantee the consistency between the reference sources. The current...

AI Technical Summary

Problems solved by technology

[0003] At present, the commonly used current source design method is to generate a reference current based on the bandgap voltage reference source added to both ends of the reference resistor, but the process error of the integrated reference resistor is very large, such as the PCM parameter of the 0.6μm CMOS Poly2 resistor is 800±150 ohms per square , the reference current value and temperature coefficient cannot be guaranteed; and if an external reference resistor is used, it will not only increase the cost, but also cannot guarantee the consistency between the reference sources

The current technical solutions have not achieved a good combination of temperature characteristics and power characteristics, especially in the design of high-precision current sources with low power supply voltages is still blank, so it is necessary to adopt a new circuit structure to achieve high-precision current sources

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