Chopping amplifier circuit coupled with sensor

Abstract

The invention provides a chopping amplifier circuit coupled with a sensor. Without an additional offset voltage regulating circuit and an additional offset temperature characteristic regulating circuit, the reduction of the offset voltage of the sensor and the influence of the temperature characteristic of the offset voltage are realized, and also low frequency noise of the sensor is effectively reduced. A Wheatstone bridge composed of one sensor and three dark units is also provided, and electrical signals are adjusted to high frequency by controlling a clock signal CLK. The offset voltage and the low frequency noise of the signals are filtered with a filter, and the signals are demodulated back to low frequency with a multiplier. The chopping amplifier circuit not only is simpler than conventional circuits, but also has a higher signal-to-noise ratio than the conventional circuits do.

Description

technical field [0001] The invention belongs to the field of weak signal detection, in particular to a chopper amplifier circuit coupled with a sensor. Background technique [0002] With the continuous improvement of the level of science and technology, the process technology of integrated circuits has been developed, which provides a guarantee for the microsystem in which the sensor and the readout circuit are integrated. With the continuous deepening of the application of micro-electro-mechanical systems in various fields of the country, people's performance requirements for micro-electro-mechanical systems are also getting higher and higher. It is specifically manifested in higher integration, higher signal-to-noise ratio, etc. [0003] For weak signal detection, the first performance to consider is the signal-to-noise ratio of the detection system. In the traditional weak signal detection system, the chopper amplifier is used to reduce the noise of the readout circuit,...

AI Technical Summary

Problems solved by technology

The problem with this method is that the offset voltage of the sensor cannot be eliminated. For example, when it is used to amplify the output voltage of the sensor bridge using piezoelectric transistors, the offset voltage of the sensor bridge cannot be eliminated due to the incomplete matching of the piezoelectric transistors, so The accuracy of the system is limited

[0005] However, conventional chopper-modulated amplifiers either as figure 1 In that way, the signal-to-noise ratio is limited by the offset voltage of the sensor, and the accuracy of the system cannot be further improved; or if figure 2 As shown, in order to improve the signal-to-noise ratio of the system, the complexity of the circuit is increased, so that the integration of the system cannot be further improved.

[0006] Furthermore, even with figure 2 The circuit shown cannot eliminate the 1 / f noise of the sensor, which limits the further improvement of the system signal-to-noise ratio

[0007] In summary, the accuracy and integration of existing chopper amplifier circuits need to be improved urgently

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