photodiode isolation amplifier circuit

Published:2011/5/7 11:30:00 Author:John | Keyword: photodiode, Isolation amplifier circuit | From:SeekIC

Photodiode isolation amplifier circuit makes the use of photodiode in order to provide reliable isolation between signal channel and power channel. IS0212P is a transformer coupled isolation amplifier circuit in small size and low cost. The inside chip uses two small but high-efficiency toroidal transformers, providing reliable isolation between signal channel and power channel. The firgue above shows the typical application in Photodetector. Photodiode BPW21 is parallelly set in two input ends of the OPAl28 (N1), causing the composition of I / U resistor gain. It adopts the amplifier feedback resistor. The selected op-amp with high impedance and low bias current aims to reduce the influence on photoelectric detection accuracy of the amplifier bias current. Amplifier OPA128 is powered by the ± V isolated power inside of the isolation amplifier ISO212P. Voltage signal of 1 / U is transformed by l00kΩ resistor into the inverting end of the input amplifier inside of IS0212P. Since the feedback resistor is R3 is also due to 100kΩ, the gain is -l.



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