A temperature compensation circuit for reference voltage

Abstract

The invention discloses a reference voltage temperature compensation circuit, which includes an operational amplifier, a first feedback resistor, and a second feedback resistor. The temperature compensation circuit includes an adjustable current source and a temperature comparator, wherein the adjustable current source One end is connected to the connection point of the first feedback resistor and the second feedback resistor; the temperature comparator is connected to the adjustable current source, senses the preset trigger temperature point, and divides the circuit operating temperature range into at least two temperature segments according to the trigger temperature point range; when the temperature comparator detects that the operating temperature is in these two temperature ranges, the temperature comparator controls the output current of the adjustable current source so that the current and the compensation voltage obtained by the first feedback resistor or the second feedback resistor are within In at least one temperature range, the preset input reference voltage adjusted by the operational amplifier and the first / second feedback resistor can be offset against the temperature variation of the voltage.

Description

technical field [0001] The invention relates to a temperature compensation circuit applied to a reference voltage of an integrated circuit. Background technique [0002] The voltage reference on the integrated circuit chip is generally generated by the bandgap reference, and the output reference voltage is usually about 1.2V; in order to improve the stability of the reference voltage, such as the stability with temperature changes, a temperature compensation is usually performed on the bandgap reference. The temperature compensation is carried out by adding the base and emitter voltage difference VBE of the triode with a negative temperature coefficient and the ΔVBE (the difference between the VBE voltages of the two triodes) with a positive temperature coefficient in an appropriate proportion. see figure 1 , shows a common prior art for voltage adjustment and output of the reference voltage VBG1 of the bandgap reference Bandgap1, where 100 is a voltage regulator, outputtin...

AI Technical Summary

Problems solved by technology

For example, a 1.25V bandgap reference voltage outputs a 2.5V reference voltage after a twice-amplified voltage regulator; the bandgap reference is set for secondary temperature compensation, and the full temperature range (-40°C-85°C ℃) voltage change is 1mV, then the change of the reference voltage output by the corresponding voltage regulator in the full temperature range is 2mV; although the relative value of the temperature drift of the reference voltage does not change, the absolute change of the reference voltage with temperature does increase doubled; moreover, the absolute variation of the reference voltage with temperature may be greater if additional temperature drift that may be introduced by the voltage regulator is taken into account

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