A Bandgap Reference Circuit with Low Offset Voltage and High Power Supply Rejection Ratio

Abstract

The invention discloses a bandgap reference circuit with low offset voltage and high power supply rejection ratio. The bandgap reference circuit comprises a voltage modulation unit (1), a bandgap core unit (2) and an operational amplifier unit (3); the voltage modulation unit Shield the noise on the power supply VDD, generate the modulation voltage VREF to supply power to the bandgap core unit and the operational amplifier unit, and improve the power supply rejection ratio; the bandgap core unit generates a bandgap reference voltage VBG with zero temperature coefficient; the operational amplifier unit ensures the first clamp The voltage VA is equal to the second clamping voltage VB, and the feedback voltage VF is output to the bandgap core unit to form a feedback loop to ensure the stability of the bandgap reference voltage VBG. The invention adopts a voltage modulation unit, which effectively improves the power supply rejection ratio; the offset voltage of the operation amplifier unit is small, and the precision of the bandgap reference voltage is improved. The invention has the characteristics of low offset voltage and high power supply rejection ratio, and can be used for analog integrated circuits.

Description

technical field [0001] The invention belongs to the technical field of analog integrated circuits, and relates to a bandgap reference circuit with low offset voltage and high power supply rejection ratio. Background technique [0002] In the field of analog integrated circuit and mixed signal integrated circuit design, the reference voltage source is one of the important components. The reference voltage source is one of the core modules of the analog circuit. Its main function is to provide a reference voltage for other modules of the chip that does not vary with temperature and supply voltage. Its performance affects the performance of the entire chip. [0003] Traditional bandgap voltage references such as figure 1 As shown, the basic principle is to superimpose the voltage with positive temperature coefficient and the voltage with negative temperature coefficient with a certain coefficient to obtain a bandgap voltage with approximately zero temperature coefficient, and ...

AI Technical Summary

Problems solved by technology

[0008] (1) In the traditional bandgap reference voltage source, the operational amplifier is used to ensure that the voltages of M and N points are equal, and the offset voltage Vos of the operational amplifier A will seriously affect the accuracy of the bandgap reference voltage VBG;

[0009] (2) The offset voltage of the operational amplifier A also has a temperature coefficient, which will affect the temperature coefficient of the bandgap reference voltage VBG;

[0010] (3) In the traditional bandgap reference voltage source technology, the operational amplifier A is powered by the power supply voltage, the noise on the power supply will directly affect the accuracy of the bandgap reference voltage VBG, and it is difficult to achieve a high power supply rejection ratio;

The voltage cascading will limit the input voltage range, and the large filter capacitor on the chip will occupy a large chip area

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