Operational amplifier-free band-gap reference circuit with pre-voltage-stabilizing structure

Abstract

The invention discloses an operational-amplifier-free band-gap reference circuit with a pre-voltage-stabilizing structure, and solves the problems in the prior art that the power supply rejection ratio is low and the offset voltage is high. The operational-amplifier-free band-gap reference circuit comprises a band-gap core unit (1), an output unit (2), a voltage pre-stabilizing unit (3) and a starting unit (4). The band-gap core unit generates a negative temperature coefficient voltage VBE and a positive temperature coefficient voltage delta VBE; the output unit generates band-gap voltage VBGand zero temperature coefficient voltage VO; the pre-voltage-stabilizing unit generates stable pre-adjusting voltage VREG by detecting feedback voltage VFB and supplies power to the band-gap core unit. The starting unit detects the bias voltage VBIAS outputted by the pre-voltage-stabilizing unit and outputs a starting signal Vstart to the pre-voltage-stabilizing unit. The pre-voltage-stabilizing structure is adopted so that the power supply rejection ratio of reference voltage is increased; the operational amplifier structure is not adopted, and the influence of offset voltage on reference voltage is weakened. The circuit is simple in structure and can be used for an analog integrated circuit.

Description

technical field [0001] The invention belongs to the technical field of circuits, in particular to a bandgap reference circuit without an op amp with a pre-stabilizing structure, which can be used for analog integrated circuits. Background technique [0002] Bandgap reference circuit is a very important module in analog integrated circuits, and is widely used in integrated circuits such as high-precision AD / DA converters, power management chips, and sensors. This module provides precise voltage for other modules in the circuit. Its characteristics such as precision and power supply rejection ratio greatly affect other performances of the whole circuit. Therefore, the bandgap with low offset, low temperature drift and high power supply rejection ratio is studied. Benchmarks have become a hot topic in analog integrated circuit design. [0003] refer to figure 1 , the basic principle of the traditional bandgap reference voltage source circuit is to add two voltage signals with...

AI Technical Summary

Problems solved by technology

[0006] The traditional bandgap reference has the following disadvantages: (1) Because the operational amplifier EA is introduced to ensure that the two points X and Y are equal, the offset voltage V OS is magnified (1+R 2 / R 3 ) times the reference voltage V BG Introduced error; (2) V OS itself varies with temperature, thus increasing the reference voltage V BG (3) The additional operational amplifier EA is introduced, which increases the power consumption of the circuit; (4) No pre-modulation structure is included, and the noise at the power supply end is directly transmitted to the output end through the operational amplifier, so the power supply rejection ratio of the circuit is not High; (5) can only generate bandgap voltage V BG , but cannot produce other voltage value output

Therefore, the accuracy and power supply rejection ratio of traditional bandgap references are difficult to meet the requirements of other modules for voltage references with low offset and high power supply rejection ratio.

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