A bandgap reference circuit to eliminate the influence of offset voltage

By using the periodic connection method of folded cascron op amp and selector in the bandgap reference circuit, the offset voltage of the input differential pair is subtracted and offset, the problem of the impact of the op amp offset voltage is solved, and small traces are achieved High-precision reference outputs for wave and low power consumption.

CN111625041BActive Publication Date: 2025-01-14WUXI ZHONGKE MICROELECTRONICS IND TECH RES INST
View PDF 1 Cites 0 Cited by

Patent Information

Application Number
CN202010624828.X
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2020-07-02
Publication Date
2025-01-14
Estimated Expiration
2040-07-02

AI Technical Summary

Technical Problem

When the prior art eliminates the influence of op amp offset voltage, it leads to large ripple of the reference voltage and requires a larger area of ​​filtering circuit, and even requires large capacity off-chip filtering capacitors, and has a large chip area and power consumption.

Method used

Using folded cascron op amp, selector and bias circuit, the offset voltage of the two input differential pairs is subtracted and canceled by periodic switching connection mode, so that the output is not subject to offset voltage in differential amplification mode. The reference voltage affected.

Benefits of technology

It effectively eliminates the influence of op amp offset voltage, has small ripple of the output reference voltage, does not require a large-area filtering network, and has very small circuit area and power consumption.

✦ Generated by Eureka AI based on patent content.

Smart Images

  • Figure CN111625041B_ABST
    Figure CN111625041B_ABST
Patent Text Reader

Abstract

The present invention belongs to the field of analog integrated circuit design, and specifically discloses a bandgap reference circuit that eliminates the influence of offset voltage, including a folded cascode operational amplifier with a PMOS and NMOS input differential pair, a selector, a bias circuit, and a bipolar bandgap output circuit; wherein the selector is controlled by a two-phase non-overlapping clock, so that the cascode operational amplifier can switch back and forth between two working modes: offset storage and differential amplification. In the offset storage mode, the connection between the cascode operational amplifier and the bandgap output circuit is disconnected, and the offset voltage is stored on the NMOS differential pair through feedback; in the differential amplification mode, the connection between the cascode operational amplifier and the bandgap output circuit is restored, and since the offset on the PMOS differential pair is offset by the offset stored on the NMOS differential pair, the cascode operational amplifier only differentially amplifies the signal from the bandgap output circuit, and the reference is not affected by the offset voltage.
Need to check novelty before this filing date? Find Prior Art

Citation Information

Patent Citations

  • Band-gap reference circuit capable of eliminating offset voltage influence

    CN212135266U