The IL300 linear optocoupler consists of an AlGaAs IRLED irradiating an isolated feedback and an output PIN photodiode in a bifurcated arrangement. The feedback photodiode captures a percentage of the LEDs flux and generates a control signal (IP1) that can be used to servo the LED drive current. This technique compensates for the LED’s non-linear, time, and temperature characteristics. The output PIN photodiode produces an output signal (IP2) that is linearly related to the servo optical flux created by the LED.
The time and temperature stability of the input-output coupler gain (K3) is insured by using matched PIN photodiodes that accurately track the output flux of the LED.