Precision current source control circuit suitable for grounded resistance sensitive sensor

Abstract

The invention relates to a precision current source control circuit suitable for a grounded resistance sensitive sensor. The precision current source control circuit comprises an instruction buffer circuit and a constant current control circuit, and specifically comprises an instruction follower IC1, a driving operational amplifier IC2, a positive end follower IC3, a negative end follower IC4, a voltage-regulator tube DW1, an instruction potentiometer RP1, a current-limiting resistor R1, a given resistor R2, a positive end resistor R3, a sampling resistor R6, a current stabilizing inductor L1, a resistance sensitive element SR1 and the like. The circuit is based on the driving operational amplifier with heavy current output and a precision sampling resistor; a circuit processing scheme that differential pressure of the sampling resistor is detected by a high-resistance follower for performing low-noise and high-precision current stabilizing power supply control is adopted; one end of the resistance sensitive sensor in the circuit disclosed by the invention can be grounded, so as to facilitate subsequent signal processing. The circuit has the advantages of fewer devices, small size and easiness for miniaturization and chip formation.

Description

technical field [0001] The invention belongs to the field of industrial measurement and control, and relates to a circuit, in particular to a precision current source control circuit suitable for a grounded resistance-sensitive sensor, which is suitable for various measurement and control applications that require one end of the resistance-sensitive sensor to be grounded. Background technique [0002] Resistive sensors such as resistance strain gauges and thermal resistors have a wide range of applications, and the type and performance of the power supply for such sensors depends on the needs of different applications, but the performance of the power supply has a significant impact on the detection results of the resistance sensor , especially in applications where one end of the resistance-sensitive sensor is required to be connected to the common ground of the subsequent signal processing circuit, the requirements for the power supply of the resistance-sensitive sensor are...

AI Technical Summary

Problems solved by technology

At present, the commonly used schemes and their shortcomings in the power supply of resistance-sensitive sensors mainly lie in: (1) scheme 1: use constant voltage power supply, the constant voltage power supply circuit is simple, but the objective noise and noise in the power supply, especially the switching power supply voltage The line voltage drop will seriously interfere with the detection results of the resistance sensor, and even endanger the normal operation of the entire measurement and control system.

(2) Scheme 2: Based on the steady current power supply scheme of detecting current through the grounding of the current sampling resistor at the end of the resistance sensor, this circuit is also easy to implement, but the resistance sensor is in a floating state, which does not meet the requirements. One end of the sensor needs to be grounded Applications

(2) Scheme 3: A steady-current power supply based on the current detection by the isolated Hall current sensor. In this scheme, although one end of the resistance-sensitive sensor can be grounded, the circuit is complex, bulky, and expensive

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