The charge-generating sensors are widely used in many applications in consumer, automotive and medical electronics. They generate a charge proportional to the applied input quantity: pressure, temperature, acceleration, strain, light, etc. Usually, charge amplifiers are used to register such signals. The charge amplifier is an integrator that integrates the input current over time. In continuous-time signal processing, a parallel resistor is used to dissipate the energy stored on the integration capacitor, and such self-zeroed integrator circuits are known as lossy integrators. To achieve low-frequency operation, when a capacitor is in the picofarad range, a very high-ohmic resistor, in the range of gigaohms, must be used. Such a high-ohmic resistor increases the output offset voltage to an unacceptable level. To overcome the output offset problems, a composite charge amplifier has been recently introduced. This paper presents an innovative lossy integrator readout circuit which contains only one opamp in the feedback. The circuit can be easily adapted to the needed gain and cut-off frequency. Its operation is validated by experimental results. The sufficiently low high-pass cut-off frequency allows the circuit to be used for biosignal amplification. Heart and respiration rates can be easily recorded with piezoelectric sensors attached to the wrist or lung wall. The presented circuit can benefit many applications where charge-to-voltage conversion is needed.

中文翻译：

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具有有源偏置点的有损积分器读出电路

电荷生成传感器广泛用于消费电子、汽车和医疗电子产品的许多应用中。它们产生与施加的输入量成正比的电荷：压力、温度、加速度、应变、光等。通常，电荷放大器用于记录此类信号。电荷放大器是一个积分器，可对输入电流随时间积分。在连续时间信号处理中，并联电阻用于耗散存储在积分电容器上的能量，这种自调零积分器电路被称为有损积分器。为了实现低频操作，当电容器在皮法范围内时，必须使用非常高欧姆的电阻器，在千兆欧范围内。这种高欧姆电阻会将输出失调电压增加到不可接受的水平。为了克服输出偏移问题，最近引入了复合电荷放大器。本文介绍了一种创新的有损积分器读出电路，该电路在反馈中仅包含一个运算放大器。该电路可以很容易地适应所需的增益和截止频率。其操作得到了实验结果的验证。足够低的高通截止频率允许电路用于生物信号放大。心脏和呼吸率可以通过贴在手腕或肺壁上的压电传感器轻松记录下来。所呈现的电路可以使许多需要电荷到电压转换的应用受益。该电路可以很容易地适应所需的增益和截止频率。其操作得到了实验结果的验证。足够低的高通截止频率允许电路用于生物信号放大。心脏和呼吸率可以通过贴在手腕或肺壁上的压电传感器轻松记录下来。所呈现的电路可以使许多需要电荷到电压转换的应用受益。该电路可以很容易地适应所需的增益和截止频率。其操作得到了实验结果的验证。足够低的高通截止频率允许电路用于生物信号放大。心脏和呼吸率可以通过贴在手腕或肺壁上的压电传感器轻松记录下来。所呈现的电路可以使许多需要电荷到电压转换的应用受益。