Homepage > Solution > Circuit analysis of AD620 application scheme
Fig. 1 Instrument amplifier circuit is composed of three amplifiers, in which resistance R and Rx should be within the range of resistance of the amplifier (1k).Ω~10kΩ) Fixed resistance R, we can adjust Rx to adjust the gain of amplification. The relationship is shown in Formula (3-20). Attention should be paid to avoid the saturation of each amplifier (the maximum output of the amplifier is its working voltage).±Vdc).
Figure 1 Instrument amplification circuit schematic diagram
Generally speaking, all the amplifiers mentioned above can be purchased with packaged products. Only one external resistor (RX) is needed to adjust the amplification rate to the required magnification according to its special relationship. Voltage and current conversion and other applications.
Fig. 2 Pressure gauge circuit
压力传感器电路图2压力测器电路AD620 特别适宜于较高电阻值， 较低电源电压的压力传感器电路设计。AD620 的体积小、功耗低成为压力传感器的重要因素， 图（1） 为3 k8、+ 5 V 电源供电的压力传感器电桥。在这样一个电路中， 电桥功耗仅为1. 7 mA ，AD620 和AD705 缓冲电压驱动器Yes信号调节，使总供电电流仅为3. 8 mA ， 同时该电路产生的噪声和漂移也极低。
Figure 3 ECG monitoring circuit
In the design of ECG monitoring circuit, the source impedance of the signal is very high and the device is portable, which requires the design of low power consumption and low supply voltage amplifier. AD620 is the best choice for this device. Fig (2) The application of AD620 in ECG monitoring circuit. Moreover, the low voltage noise of AD620 improves the dynamic range and makes the monitoring circuit have better performance. In order to maintain the stability of the driving loop in the diagram, the capacitance C1 value should be selected appropriately.
Figure 4 Precise Voltage-Current Conversion
Fig. 5 Application Circuit
Since the peak value of the output signal of the sinusoidal signal generator is about 1V and the voltage drop on the sampling resistance connected in series with the network load is very small, the sampled signal should be amplified. Two-stage amplification is used, and AD620 is used in the preamplifier. AD620 is a kind of instrument amplifier with low power consumption, especially suitable for small signal preamplifier. The distortion of small signal amplified by AD620 is very small, and the preamplifier composed of one stage AD620 can also control the system error within the range of system design requirements. The preamplifier circuit is shown in the figure.
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