A novel passive interface circuit with gain for nongenerating (active, i.e., excited/driven) sensors in differential or bridge configuration is presented. The circuit is very simple and consists of only one transformer in the output diagonal of the equivalent bridge configuration comprised of sensor(s), bridge completion impedances, and excitation source. It can be used with resistive, capacitive, inductive, eddy-current, and similar sensors for measurement of temperature, displacement, pressure, torque, etc. The gain achieved depends on the transformer voltage ratio, $n$ . Unlike the usual transformer application for voltage raise (gain) where the gain is proportional to $n$ , in this circuit, the high gain is achieved with $n$ close to 1. This is due to positive feedback introduced into the circuit. Transformers with voltage ratios close to 1 exhibit much less leakage and smaller losses which can degrade the (ideal) gain. With current on-chip transformers or miniature transformers available on the market, the practical gain can reach 20 dB. The circuit can be easily integrated into various MEMS sensors. As the circuit is entirely passive, its application extends far beyond the usual semiconductor temperature limits. Depending on the transformer technology, the circuit can be used in a very cold (e.g., cryogenic) or very hot environment (e.g., steam and gas turbines, jet engines, rockets, down-hole drilling, etc.) or exposed to nuclear radiation.

中文翻译：

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一种具有增益的新型无源接口电路，用于差分或桥式配置的非生成传感器

提出了一种具有增益的新型无源接口电路，用于差分或桥式配置的非生成（有源，即激励/驱动）传感器。该电路非常简单，在等效电桥配置的输出对角线上仅包含一个变压器，该配置由传感器、电桥完成阻抗和激励源组成。它可以与电阻、电容、电感、涡流和类似传感器一起使用，用于测量温度、位移、压力、扭矩等。实现的增益取决于变压器电压比， $n$ . 不同于通常的电压升高（增益）变压器应用，其中增益与 $n$ ，在这个电路中，高增益是通过 $n$ 接近 1。这是由于引入电路的正反馈。电压比接近 1 的变压器表现出更少的泄漏和更小的损耗，这会降低（理想的）增益。目前市面上的片上变压器或微型变压器，实际增益可达20dB。该电路可以很容易地集成到各种 MEMS 传感器中。由于该电路是完全无源的，其应用范围远远超出了通常的半导体温度限制。根据变压器技术，该电路可用于极冷（如低温）或极热环境（如蒸汽和燃气轮机、喷气发动机、火箭、井下钻探等）或暴露于核辐射.