High-precision current reference circuit

Abstract

The invention provides a high-precision current reference circuit. The circuit comprises multiple MOS transistors, a polycrystalline silicon resistor R1, a polycrystalline silicon resistor R0, a PNP triode Q1, a PNP triode Q2 and the like, wherein the Q2 and the R0 are connected in parallel, the Q1 and the R1 are connected in parallel, the mode that the triodes and the polycrystalline silicon resistors are connected in parallel is the core architecture of the circuit, NM2 and NM3 form a current mirror, NM0 and NM1 form a current mirror, and bias current of the current mirrors comes from superimposed current of the triodes and the polycrystalline silicon resistors; finally, positive temperature coefficient current obtained through output of a current mirror formed by PM7 and PM8 and negative temperature coefficient current obtained through output of a current mirror formed by PM4 and PM5 are mutually overlaid, and reference current Iref irrelevant to the temperature is obtained. Accordingly, relative to a general classic current reference circuit, the structure is simple, a better temperature coefficient is achieved, and the circuit cost and use cost are lowered.

Description

technical field [0001] The invention relates to the technical field of integrated circuits, in particular to a high-precision current reference circuit. Background technique [0002] Due to the continuous innovation of the integrated circuit industry, in the digital-analog hybrid or analog integrated circuits, the reference source in the chip has always been a research hotspot. In addition to the voltage reference source with high frequency, the current reference has also received more and more attention. application. Especially in providing bias current for other circuit modules, such as operational amplifiers, oscillators, and high-precision A / D converters and other related analog circuits, most of them use current as a reference. To optimize the performance of commonly used circuits, the requirements for reference current are becoming more and more stringent, so it is particularly critical to create a current reference that has basically nothing to do with power supply a...

AI Technical Summary

Problems solved by technology

However, due to the existence of the amplifier and the influence of the temperature characteristics of the resistor R1, we say that the circuit has the problem of input offset, the accuracy is not particularly high, and the structure of the amplifier is complicated to design, occupying a large area of ​​the layout, etc., and due to The requirements of actual projects are getting higher and higher, and the circuit structure with high precision, simplicity and good performance is very critical.

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