Current temperature sensor circuit for CMOS switch and control method thereof

Abstract

The present invention relates to a current temperature sensor circuit for CMOS switch and control method thereof. The sensor circuit comprises a voltage generation circuit, an operational amplifier, an input capacitor, a feedback capacitor, a resistance voltage divider, a control circuit and several MOS switches. The voltage generation circuit is connected with an external power supply to output the first interelectrode voltage and the second interelectrode voltage. An out-phase input of the operational amplifier is connected with the voltage generation circuit through the input capacitor to receive the first interelectrode voltage while the in-phase input receives the second interelectrode voltage; and the output of the operational amplifier is divided into two paths which respectively output reference voltage and positive temperature coefficient voltage. By utilizing dynamic element matching technique, the current temperature sensor circuit can generate an accurate amplifying coefficient for a small voltage difference delta Vbe, and generate accurate reference voltage independent of temperature and positive temperature coefficient voltage varying in direct proportion to temperature, thus effectively improving temperature detection accuracy of the temperature sensor.

Description

technical field [0001] The invention relates to the field of sensors, in particular to a CMOS switch current temperature sensor circuit and a control method thereof that can be widely used in temperature protection modules and industrial process control systems. Background technique [0002] In the process of industrial and agricultural production and scientific research, temperature is an important parameter that needs to be measured and controlled. Therefore, among various sensors, temperature sensors are the most widely used ones, and CMOS temperature sensors are different from traditional temperature sensors. It has the advantages of high sensitivity, good linearity, small size, low power consumption, and easy integration, so it has a prominent position in the field of temperature sensor applications. [0003] However, due to the limitation of the accuracy of PTAT (Proportional To Absolute Temperature, which changes in direct proportion to temperature) voltage, ordinary ...

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Problems solved by technology

[0003] However, due to the limitation of the accuracy of PTAT (Proportional To Absolute Temperature, which changes in direct proportion to temperature) voltage, ordinary CMOS temperature sensors have two main defects: one is the mismatch of bipolar transistor pairs; the other is the current composed of MOS transistors Source Circuit Mismatch

Therefore, due to these two defects, the relative error of the voltage difference between the base and emitter of the bipolar transistor pair will be greatly increased, resulting in inaccurate temperature detection by the temperature sensor.

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