High-reliability sensor reading circuit

Abstract

The invention discloses a sensor reading circuit with high reliability. The circuit comprises a control logic module, a sample hold circuit, a modulator and a digital filter. The oscillator generatesa periodic square wave signal CK0, the frequency of the square wave signal CK0 is Fs, and the period T is equal to 1 / Fs. The square wave CK0 generates CK1 and CK2 signals through control logic, and the CK1 is a control signal of the sampling and holding circuit and is used for controlling the sampling and holding circuit to sample, amplify and hold a Vs signal output by the sensor; the CK2 controls the Sigma Delta modulator to sample and convert the Sigma Delta modulator into a single-bit or multi-bit data stream Qsdm, wherein the average value of Qsdm is equal to Vsh. A Qsdm data stream is down-sampled by a digital filter and converted into a multi-bit digital output Data, and meanwhile, when one conversion is completed, an EOC signal is generated and is used for closing OSC and Ctrl Logic modules, so that the power consumption is reduced. According to the sensor reading circuit provided by the invention, through alternate sampling and conversion, the design requirements of a specialprocess and a quickly established ADC are avoided, and the universality and reliability of the sensor reading circuit are greatly improved.

Description

technical field [0001] The invention relates to the field of sensor output, in particular to a highly reliable sensor readout circuit. Background technique [0002] Whether in life or industrial applications, sensors are everywhere. The temperature control of refrigerators and air conditioners requires temperature sensors, the humidity control of agricultural soil requires humidity sensors, human blood sugar monitoring, electrocardiogram detection, car tire pressure detection, etc. all require sensors. For industry, there is no industrial automation without sensors. The sensor network, one of the new research hotspots in the information field, uses a large number of sensors to collect data. One of the characteristics of the sensor network is large scale, that is, the sensor network is generally composed of a large number of sensor nodes, and the number of nodes may reach tens of thousands or even more. [0003] A sensor is a detection device that can convert a change in a...

AI Technical Summary

Problems solved by technology

Due to the time required for ADC conversion, during the ADC conversion process, due to the limitation of integrated circuit technology, there are different degrees of leakage at the output node. This leakage causes the voltage on the output node to completely deviate from the original voltage before the conversion of the ADC is completed. The sample and hold value, especially as the temperature rises, the leakage will increase significantly, which seriously affects the accuracy of the entire sensor readout circuit

[0008] At present, there are two common methods to solve the reduction of ADC conversion accuracy caused by mining and protection leakage. One is to use low leakage technology, which puts forward requirements for the selection of technology, and sometimes low leakage technology cannot meet other requirements; the second method It is to try to increase the conversion speed of the ADC, and complete the conversion before the amplitude change introduced by the leakage reaches 1 LSB (LeastSignificant Bit, least significant bit)

However, the improvement of ADC conversion speed increases the difficulty of design and increases the power consumption of ADC, especially for systems with strict power consumption requirements, such as sensor readout circuits in wearable devices, ADC cannot be accelerated by increasing the oversampling rate. The conversion speed of the ADC, which will cause the ADC to consume a lot of power

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