CMUTs resonant signal output network based on MOSFET

Abstract

The invention discloses a CMUTs resonant signal output network based on an MOSFET. The CMUTs resonant signal output network comprises a bias network, a CMUTs, a coupling capacitor, a positive voltage, a negative voltage, an NMOS network, a PMOS network, a feedback resistor, a feedback capacitor, a filter network, an inverter and a frequency counter. The bias network provides direct current voltage for the CMUTs and avoids current overload; the PMOS network and the NMOS network are used for providing gains for small oscillation signals; the feedback resistor enables the PMOS network and the NMOS network to be located in the same transition region; and the feedback capacitor attenuates a low frequency oscillation signal. The method is based on the self logic feedback principle of the MOSFET; a resonant circuit applying PMOS and NMOS is designed, is good in compatibility with a COMS process, adapts to CMUTs with different frequencies, can shape and amplify an oscillation waveform and output the resonant frequency of the CMUTs in real time, and has important significance for integration and real-time detection application of the CMUTs resonant biochemical sensor.

Description

technical field [0001] The invention belongs to the technical field of MEMS sensor electronic measurement, in particular to a resonant circuit of a CMUTs (Capacitive Micromachined Ultrasonic Transducers, capacitive micromachined ultrasonic transducer) resonant biochemical sensor. Background technique [0002] The CMUTs resonant biochemical sensor is manufactured by MEMS technology, which is compatible with CMOS technology. It integrates the back-end resonant circuit, which can detect trace biochemical substances in real time, and form a miniaturized array. The detection sensitivity can reach the ppb level. Compared with the biochemical sensors based on micro-cantilever, surface acoustic wave and film bulk acoustic wave principles, the resonant biochemical sensors using CMUTs have the advantages of detection sensitivity, signal integration processing, array working mode, functional convenience and uniformity of array units, etc. It has great advantages and is regarded as the ...

AI Technical Summary

Problems solved by technology

[0005] To sum up, since CMUTs are based on the capacitance detection principle, limited by the processing technology and structure, their capacitance parasitics will greatly affect the impedance characteristics of the CMUTs array, especially when loaded with low DC bias voltage (several volts to tens of volts). ), it is difficult to form capacitive and inductive mutual conversion; the amplified feedback circuit based on the triode can realize the output of CMUTs resonance signal, but it is not compatible with the CMOS process, which is not conducive to the miniaturization, integration and integrated design and development of CMUTs in the future, and even more It is not conducive to integration with portable devices; in addition, the circuit based on the triode can only be specially designed for a single working state of a CMUTs chip, and the device parameters need to be changed again for CMUTs of different frequencies, which has poor adaptability

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