Environmental gradual change self-adaptive capacitive sensing detection system

Abstract

The invention relates to the technical field of capacitive sensing detection, in particular to an environment gradual change self-adaptive capacitive sensing detection system which comprises an analog system and a digital system. The simulation system comprises a gating circuit and a simulation processing circuit. The digital system comprises a counter, a shift data difference subtractor, a comparison decision device, a one-time programmable memory, a data latch and a digital main control circuit. In the detection process of the system, an ADC does not need to participate in conversion detection, and the power consumption of the system is remarkably reduced; the threshold environment self-adaptive algorithm is executed, the threshold does not drift, when the system is delivered to a client, the client can directly use the system after simple OTP programming, re-development is not needed, and the system is convenient to use.

Description

technical field [0001] The invention relates to the technical field of capacitive sensing detection, in particular to a slowly changing environment self-adaptive capacitive sensing detection system. Background technique [0002] The principle of the existing capacitive sensing detection system is generally as follows: the circuit has an emitter TX and a receiving electrode RX, and the capacitor sub-capacitance or mutual capacitance is first converted into an electrical signal, and then through the ADC circuit, the voltage signal is digitized to obtain a specific The digital quantization value is judged by the judgment logic to give a conclusion based on the numerical quantization value. like figure 1 As shown, the invention patent of Chinese Patent Publication No. CN107247529A discloses a capacitive sensing detection scheme. It can be seen from the scheme that the capacitive sensing circuit has an emitter TX and a receiving pole RX. The capacitance is first converted into ...

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Problems solved by technology

This is because the slow change of the environment will lead to the drift of the output result (the value changes slowly), and the change brought by the environment change is different from the rapid change of the noise introduced by the interference. Therefore, a noise threshold needs to be set here, and noise judgment is required. , and the baseline update, and the judgment here is based on an absolute value, and then set the threshold, hysteresis range, baseline, noise threshold, etc. on the basis of the absolute value, so the data to be processed is huge and complex, so MCU + algorithm is required to cooperate with the processing In order to complete the final judgment, which in turn increases the system's demand for resources

In summary, this traditional capacitive sensing detection system not only has a complex circuit structure, but also requires AD conversion, and the conversion structure from capacitance to voltage (that is, C2V) is easily affected by external interference. The judgment process needs to be processed by MCU or filter, which eventually leads to The system has high complexity, large area, high cost and energy consumption, which is not conducive to the promotion and application of the system

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