一种用于电阻式传感器的线性灵敏有源半桥电路及其补偿

Linear sensitive active half bridge circuit and its compensation for resistive sensors

为了实现由非常小的物理量或化学分析物变化引起的电阻式传感器的小电阻变化的测量,提出了一种低成本、高精度的电阻式传感器精密电子电路的设计。电路由一个有源半桥电路和一个反相加法放大器构成,仅需要很少的元件作为其硬件实现;分析了提出电路的工作原理,并对由于环境温度、连接导线电阻和输入激励电压对测量电路输出造成的影响进行了分析研究。理论分析结果表明,采用所提出的线性灵敏有源半桥电路,环境温度和连接导线电阻对测量电路输出造成的影响几乎可以忽略不计,而输入激励波动的影响可以通过归一化技术来消除。与传统全桥式和半桥式电路的比较实验结果表明,所提出的有源半电桥电路的灵敏度几乎是传统半桥电路的4倍,是传统全电桥电路的2倍;同时还验证了环境温度和连接导线电阻对电路的输出影响很小。

In order to realize the measurement of small resistance change for resistive sensors caused by change in very little physical quantity or chemical analytes, a low cost and high precision electronic circuit for resistive sensors is proposed in this paper. The circuit consists of an active half bridge circuit and an inverting adder amplifier, which requiring only a few components for its hardware implementation. The working principle of the proposed circuit is analyzed, and the effect on the output of the measuring circuit due to ambient temperature, connecting lead resistance and input excitation voltage is analyzed and studied. The theoretical analysis results show that the effect on the output of the measuring circuit due to ambient temperature and connecting lead resistance the is almost negligible by using the proposed linear sensitive active bridge circuit, while the effect due to fluctuation of input excitation voltage can be eliminated by normalization technology. The experimental results, compared with the traditional full bridge and half bridge circuit, show that the active half bridge circuit is almost four times more sensitive than conventional half bridge circuit and two times more sensitive than traditional full bridge circuit. At the same time, it is also proved that the ambient temperature and the connecting lead resistance have little effect on the output of the circuit.