Band-gap reference voltage producing circuit

Abstract

The invention provides a novel high-precision full-period output switch capacitor band-gap voltage producing circuit for meeting the demand of a high-precision increment ADC to the precision of a reference voltage. A dual-rotary single-switch capacitor operation amplifier structure is used by the circuit structure to eliminate the influence of the operation amplifier input offset voltage as well as reduce the limited gain error of the operation amplifier; the invention further comprises two same switch capacitor band-gap reference producing circuits with complementary clock periods; and meanwhile, a gating switch is connected in series with each output end, thereby, realizing the full-period band-gap reference voltage output.

Description

technical field [0001] The invention relates to the field of integrated circuits, in particular to the field of bandgap references in tire pressure monitoring systems. Background technique [0002] With the rise of the Internet of Things, multi-sensor integration and intelligent processing of sensor signals have become a trend. It is urgent to realize a high-precision digital-to-analog conversion interface between the analog signal of the sensor and the digital interface of the microprocessor. The interface should include a high-precision bandgap reference voltage generation circuit integrated within the chip. [0003] Generally speaking, since the signal bandwidth of the sensor is not very large (such as piezoresistive sensor, temperature sensor, magnetic sensor, etc.), and the signal sensitivity is small, an incremental ADC is generally used to quantify the sensor signal. Since there are two non-overlapping clocks in the system, it is a better choice to use a switched cap...

AI Technical Summary

Problems solved by technology

[0004] In addition, there are many error sources in the bandgap reference voltage generation circuit, such as process deviation, operational amplifier input offset voltage, operational amplifier finite gain error, transistor mismatch, resistor ratio mismatch, etc., which will introduce various errors to the ADC reference voltage

Although various techniques exist to eliminate or reduce various sources of error, there are still some limitations for high-precision sensor application requirements

[0005] For example, the conventional chopper modulation op amp technology can eliminate the input offset and charge injection effect of the op amp, but it cannot play a good role in incremental ADCs, especially for incremental ADCs with two or more orders. Inhibition, the reason is that the digital filter of the high-order incremental ADC has different weights on the quantized output, which causes the offset voltage cancellation technology of chopping modulation to fail to achieve the expected performance

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