A disconnection detection circuit and temperature acquisition circuit

Abstract

The invention discloses a disconnection detection circuit and a temperature acquisition circuit, through a first diode, a second diode, a first constant current source, a second constant current source, a first switch, a second switch, a first Resistor, second resistor, third resistor, fourth resistor, fifth resistor, filter amplifier circuit, analog-to-digital conversion ADC chip connection relationship and on-off control of the circuit, to realize the on-off detection of the temperature sensor, and realize the use of the same A circuit detects whether the connection of the thermocouple sensor and the thermal resistance sensor is normal. The disconnection detection circuit disclosed by the present invention realizes the use of an ordinary ADC chip without a thermal resistance disconnection detection function. The unique ADC chip without thermal resistance disconnection detection function makes the cost of the disconnection detection circuit lower, which is convenient for wide popularization and use. In addition, the circuit structure is simple and the reliability is high.

Description

technical field [0001] The invention relates to the field of disconnection detection, in particular to a disconnection detection circuit and a temperature acquisition circuit. Background technique [0002] Temperature acquisition instruments generally have a built-in disconnection detection circuit, which is used to automatically detect whether the connection between the temperature sensor and the instrument is normal. [0003] Commonly used temperature sensors include thermal resistance sensors and thermocouple sensors, and the working principles of thermal resistance sensors and thermocouple sensors are different, resulting in different disconnection detection circuits for thermal resistance sensors and thermocouple sensors. [0004] Therefore, designing a general-purpose disconnection detection circuit has become the primary task, which can be connected to both thermocouple sensors and thermal resistance sensors. At present, it is commonly used to select an ADC (Analog-t...

AI Technical Summary

Problems solved by technology

[0006] In view of this, the present invention provides a disconnection detection circuit and a temperature acquisition circuit to solve the problem in the prior art that the ADC chip with thermal resistance disconnection detection function is expensive and difficult to popularize. The specific scheme is as follows:

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