Chopping band-gap reference circuit based on CMOS process and reference voltage chip

Abstract

The invention belongs to the field of integrated circuit, and provides a chopping band-gap reference circuit based on the CMOS process and a reference voltage chip. The chopping band-gap reference circuit comprises a modulation unit, a chopping operational amplifier unit, a demodulation unit and a filtering unit. The modulation unit is provided with a plurality of chopping modulation switches, reference voltages with the positive temperature coefficients and the negative temperature coefficients are controlled and generated by the chopping modulation switches, and the relative positive voltage deviation and the negative voltage deviation exist in the reference voltages. The chopping operational amplifier unit chops the reference voltages and feeds back the reference voltages to the modulation unit, the reference voltages are modulated to high frequency, and then offset voltages and noise are generated at the same time. The high frequency reference voltages are demodulated to fundamental frequency by the demodulation unit, and the offset voltages and the noise are modulated to high frequency. The filtering unit filters the high frequency offset voltages and the noise, and the reference voltages with the positive voltage deviation and the negative voltage deviation are summed and averaged. According to the band-gap reference circuit with the chopping structure, accuracy of the reference voltages is improved, by the utilization of the chopping modulation switches and the filtering unit, the influences of the defective process on the reference voltages are avoided, and consistency and the temperature characteristics of the reference voltages are improved.

Description

technical field [0001] The invention belongs to the field of integrated circuits, in particular to a chopper bandgap reference circuit and a reference voltage chip based on CMOS technology. Background technique [0002] At present, due to the rapid development of the integrated circuit industry, the development of portable electronic products has been greatly promoted. As some basic application circuits, such as digital-to-analog / analog-to-digital converters, phase-locked loops, and filters, etc., high-performance bandgap reference circuits are required to provide them with high-precision, good consistency, and low temperature coefficient reference circuits. Voltage. [0003] Due to the defects of the CMOS manufacturing process, there is a certain offset voltage in the op amp, and the output voltage of the op amp is not zero when the input of the op amp is zero, and the accuracy of the reference voltage is low. Therefore, in order to eliminate the influence of the offset an...

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Problems solved by technology

[0005] The purpose of the embodiments of the present invention is to provide a chopper bandgap reference circuit based on CMOS technology, aiming at solving the large difference in reference voltage and poor temperature characteristics of the chopper bandgap reference circuit due to process defects under the current CMOS technology. , and it is necessary to add a trimming circuit to trim the reference voltage, resulting in high cost

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