I am sorry.
...You must apply through a resistor negative bias...
You even specify the type of optocoupler.
Bordodynov.
02.08.2016, 08:05, "§¡§Ý§Ö§Ü§ã§Ñ§ß§Õ§â §¢§à§â§Õ§à§Õ§í§ß§à§Ó BordodunovAlex@... [LTspice]" <ltspice@...>:
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Hey. You are probably accessing the telepaths. I do not know the elementary photodetectors elements having an output value of the line voltage. If the primary receiver is a pn junction, it produces current. Having loaded his resistance, can be obtained linearly varying voltage, before starting a pn junction. Neohodimo through resistor feeding a negative bias. For example, one pin resistor connected to the positive supply. See datasheet optocoupler.
Bordodynov.
02.08.2016, 07:19, "skip@... [LTspice]" <ltspice@...>:
I have a requirement to model an optoisolator in LTSpice. The optoisolator has an input LED that shines light on a photovoltaic cell on the output. Current in the LED will cause light to fall on the photovoltaic cell and cause a voltage to be generated on the output. I have measured the input-current-to-output-voltage characteristics of the device - Vout=F(Iin). The transfer function F is somewhat nonlinear. I have created a table of measurements listing the output voltage for a set of specific input currents. Now I am trying to build an LTSpice model that functions similarly to the actual device.
A simple first-order approximation of the device would be a current-controlled voltage source with the transfer function defined as a table. i have tried all kinds of ways to define the table in a LTSpice current-controlled-voltage-source, but no luck. Can anyone show me how to do this? What does the spice directive look like, and where (and how) do you put it in LTSpice?
A second-order model will need to take into account that output impedance will also affect the output voltage (at low impedances the output becomes more like ?a current source), but that is for another day.
