A Low Noise Bandgap Reference Circuit with Reduced Offset Effect

Abstract

The invention relates to a low-noise bandgap reference circuit for reducing offset influence, which belongs to the field of integrated circuits. Including current source module, PTAT voltage generation module and bandgap reference voltage generation module, PTAT voltage generation module is used to generate PTAT voltage; The two branches in the gap reference voltage generation module provide proportional current; the band gap reference voltage generation module is used to generate the band gap reference voltage using the PTAT voltage. The bandgap reference circuit proposed in the present invention uses the operational amplifier to clamp the ratio of the collector currents flowing through the two NPN transistors, and realizes the difference in the base-emitter voltage difference of the two NPN transistors through voltage superposition, which significantly reduces the Gain of input offset voltage and noise voltage to bandgap reference output voltage, thereby reducing the effect of op amp offset and noise on output voltage.

Description

technical field [0001] The invention belongs to the field of integrated circuits, and relates to a bandgap reference circuit in the integrated circuit, in particular to a low-noise bandgap reference circuit which reduces the influence of offset. Background technique [0002] The reference voltage source is a type of circuit widely used in integrated circuits. It can provide accurate voltage reference signals for other modules in the integrated circuit. The "bandgap" reference has become a recognized voltage reference technology. Its basic structure is as follows: figure 1 As shown, the operational amplifier in this circuit is used to clamp the X and Y point voltage V X and V Y , making V X =V Y . The specific principle of the bandgap reference circuit is as follows: [0003] The relationship between the voltage and current of the triode is: [0004] [0005] Among them, V BE It is the voltage difference between the base and the emitter of the triode, generally betw...

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Problems solved by technology

[0025] Aiming at the deficiencies of the above-mentioned traditional bandgap reference circuit, such as the large error of the output terminal voltage caused by the offset and noise, and the inapplicability to low-voltage applications, the present invention proposes a high power supply rejection ratio bandgap reference circuit, using the calculation The amplifier is used to clamp the ratio of the collector current flowing through the two NPN transistors, and realize the difference between the base-emitter voltage difference of the two NPN transistors through voltage superposition, which can effectively reduce the offset voltage and noise voltage of the op amp to the output voltage effect, can be applied in low pressure environment

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