Photodiode isolation amplifier circuit diagram composed of ISO212P

IS0212P is a low-cost and miniaturized transformer-coupled isolation amplifier circuit. It uses two high-efficiency small toroidal transformers on-chip to provide reliable isolation between the signal and power channels.

As shown in the figure is a typical application of IS0212P in photoelectric detection. The photodiode BPW21 is connected to the two input terminals of OPAl28 (N1) to form the I/U resistor gain, and an amplified feedback resistor is selected. A high-impedance, low-bias current operational amplifier is used here to reduce the impact of the operational amplifier bias current on the photoelectric detection accuracy. The OPA128 is powered by the ±V isolated supply inside the isolation amplifier ISO212P. The 1/U converted voltage signal is sent to the inverting end of the input amplifier of the IS0212P through a 100kΩ resistor. Since the feedback resistor R3 is also 100kΩ, its gain is -l.

The photodiode isolation amplifier circuit uses photodiodes to provide reliable isolation between the signal and power channels. This circuit can realize the isolation amplification function in photoelectric detection!