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采集要求电流隔离的低电平信号,如来自有电噪声环境中的热电偶温度传感器的信号,会产生一个难以解决但有时是不可避免的设计问题.市售的隔离放大器,尽管使用方便而且也适合连接高电平信号,但是有很大的零失凋误差和漂移(每C分别为几mV和几十μV).这使得它们不适合处理某些传感器的微伏输出.与此不同,本文所描述的放大器的零失凋误差和漂移一般可达到3μV和0.01μV/C,这比通常的隔离放大器好三个数量级.它采用了斩波器稳定的微功率LTC1047 以及光耦合电路(见图).由于电流隔离器件对每一个通道都需要一个独立的隔离电源,所以此电路把使用方便性提高到最大限度,因为它具有独特的处理双极信号的能力,而
Acquiring low level signals that require galvanic isolation, such as those from thermocouple temperature sensors in electrically noisy environments, creates an unresolved but sometimes unavoidable design problem. Commercially available isolation amplifiers, though easy to use and also Suitable for connecting high-level signals, but with large zero-glitch errors and drifts (a few mV and several tens of μV per C, respectively), making them unsuitable for handling the micro-volt output of some sensors In contrast, The zero-drift error and drift of the amplifier described are typically up to 3μV and 0.01μV / C, which is three orders of magnitude better than typical isolated amplifiers, using a chopper-stabilized micro-power LTC1047 and an optocoupler ) Because current-sink devices require a separate isolated power supply for each channel, this circuit maximizes ease of use because of its unique ability to handle bipolar signals while