Built-in self test circuit and self test method for parallel plate capacitive MEMS (Micro-Electro-Mechanical-System) accelerometer

Abstract

The invention provides a built-in self test circuit for a parallel plate capacitive MEMS (Micro-Electro-Mechanical-System) accelerometer and a self test method. Electric excitation is provided for the parallel plate capacitive accelerometer, signals outputted by a capacitive sensing module are simplified and subjected to analog-to-digital conversion and digital processing, the sensitivity S is analyzed according to self test power supply voltages V1 and V2 in different conditions and an output response Vc of the capacitive sensing module, technical defects of the parallel plate capacitive MEMS accelerometer are then diagnosed, and built-in self test is carried out on the sensitivity S of the capacitive accelerometer. Influences on output signals by the external environment and parasitic capacitance are optimized, the test standardization degree is improved, dependence on a complicated test instruction is reduced, and the test cost and the product cost are effectively reduced.

Description

technical field [0001] The invention relates to a parallel-plate capacitive MEMS accelerometer, in particular to a parallel-plate capacitive MEMS accelerometer with a built-in self-test circuit and a corresponding self-test method. Background technique [0002] MEMS (Micro-Electro-Mechanical-System) technology is gradually developed on the basis of microelectronics manufacturing technology by absorbing and integrating other processing technology. It refers to micro-devices or micro-systems that can be mass-produced using micro-machining technology, integrating micro-sensors, micro-mechanisms, micro-actuators, signal processing and control circuits, interfaces, and communications. MEMS technology originated in the 1950s and 1960s, but with the rapid development of device technology, MEMS technology has been applied to almost all fields, especially high-tech fields that require small size, high precision, high reliability and low power consumption. Great changes have taken pl...

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Problems solved by technology

[0005] However, since most of the MEMS accelerometer tests in the past used a more complex physical stimulus, such as force F and acceleration a, the whole process was time-consuming and labor-intensive, reducing production efficiency; at the same time, the parallel plate capacitive MEMS accelerometer It has a complex micro-mechanical structure inside, which is easily affected by the external environment and parasitic capacitance. The mechanism of testing this device is becoming more and more complicated, and the test cost generated by using off-chip high-precision test equipment is also high

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