A High Precision Fully Differential Capacitance-Voltage Conversion Circuit System

Abstract

The invention relates to the field of MEMS (Micro Electro Mechanical System) inertial devices, in particular to a high-accuracy fully differential capacitance-voltage conversion circuit system. The high-accuracy fully differential capacitance-voltage conversion circuit system comprises a driving signal generation part, a fully differential charge amplifier and capacitance compensation arrays. A whole conversion circuit and a sensor sensitive structure still adopt an output mode in single-ended connection, and a fully differential circuit structure is realized through time division multiplexing; a circuit adopts a switch capacitance structure for removing the influence of parasitic capacitance, main signal channels adopt a correlated double sampling technology for removing low-frequency noise and detuning, the capacitance compensation array is capable of correcting the detuning and non-linearity of the sensor sensitive structure. According to the high-accuracy fully differential capacitance-voltage conversion circuit system disclosed by the invention, the influence of the parasitic capacitance can be effectively inhibited, common-mode interference generated by switch charge injection and substrate noise can be reduced, harmonic distortion of the circuit is reduced, the linearity of an accelerometer system is increased, and zero drift is inhibited.

Description

technical field

[0001] The invention relates to the field of MEMS inertial devices, in particular to a high-precision fully differential capacitance-voltage conversion circuit system. Background technique

[0002] Acceleration sensors can convert weak acceleration physical signals into electrical signals that can be detected. High-precision acceleration sensors are widely used in earthquake detection, automotive safety, aerospace, space microgravity measurement and other measurement fields that require high precision. People began to study the structure and manufacturing technology of the acceleration sensor very early. With the development and popularization of MEMS technology in recent years, the integration of microelectronics technology and mechanical engineering makes the acceleration sensor no matter in structure or performance. There have been great improvements and improvements. Capacitive acceleration sensor is currently the most researched type of acceleration sen...

Examples

Embodiment Construction

[0025] The present invention will be further described below in conjunction with accompanying drawing:

[0026] figure 1 It is a traditional single-ended detection circuit. The overall circuit adopts a single-ended charge amplifier and a switched capacitor structure, which can effectively reduce the influence of parasitic capacitance and improve the accuracy of circuit switching. The working process of the circuit is the charge detection stage and the charge transfer stage. In the charge detection stage: p1 is high level, p2 is low level, p3 is low level, and the sensitive capacitor C S1 and C S2 The upper and lower pole plates are respectively connected to V - and V + , at this time stored in the sensitive capacitor C S1 and C S2 The charges are V + C S1 and V - C S2 . P4 is low level, p5 is high level, the output of the operational amplifier is shorted to the input, the output of the operational amplifier is 0, and the integral capacitor C f Both ends are grounded...

technical field

[0001] The invention relates to the field of MEMS inertial devices, in particular to a high-precision fully differential capacitance-voltage conversion circuit system. Background technique

[0002] Acceleration sensors can convert weak acceleration physical signals into electrical signals that can be detected. High-precision acceleration sensors are widely used in earthquake detection, automotive safety, aerospace, space microgravity measurement and other measurement fields that require high precision. People began to study the structure and manufacturing technology of the acceleration sensor very early. With the development and popularization of MEMS technology in recent years, the integration of microelectronics technology and mechanical engineering makes the acceleration sensor no matter in structure or performance. There have been great improvements and improvements. Capacitive acceleration sensor is currently the most researched type of acceleration sen...

Examples

Embodiment Construction

[0025] The present invention will be further described below in conjunction with accompanying drawing:

[0026] figure 1 It is a traditional single-ended detection circuit. The overall circuit adopts a single-ended charge amplifier and a switched capacitor structure, which can effectively reduce the influence of parasitic capacitance and improve the accuracy of circuit switching. The working process of the circuit is the charge detection stage and the charge transfer stage. In the charge detection stage: p1 is high level, p2 is low level, p3 is low level, and the sensitive capacitor C S1 and C S2 The upper and lower pole plates are respectively connected to V - and V + , at this time stored in the sensitive capacitor C S1 and C S2 The charges are V + C S1 and V - C S2 . P4 is low level, p5 is high level, the output of the operational amplifier is shorted to the input, the output of the operational amplifier is 0, and the integral capacitor C f Both ends are grounded...

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