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What are some tips for modeling optocouplers for Pspice?7 @6 r% B& q" S( T7 P5 B6 Z6 z
Though Model Editor does not provide a template for either an optocoupler or for a phototransistor, it can beused create components of these models. For example,you can use Model Editor to model the electricalcharacteristics of the input LED of an optocoupler.
) M/ C- C% Q5 w* |( z! jIn the case of the optocoupler，you need to create a model for a LED input，and also for a single BJTphototransistor output optocoupler.
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To model LED input, fit the forward current vs. voltage curve of the LED, and the LED capacitance curve toa PSpice diode. These curves are available in datasheets.
- j Y& l6 T& a: N& \2.CTR curve fit( c/ s8 H9 @0 J5 b
Use Mathcad or Excel to fit the CTR curve to a polynomial. A polynomial which may work is of the formA*exp(B+Cx).) Z/ s, E( } x! P9 U n0 D' X0 F4 {
In the sample model shown below, the Gpcg source models the CTR curve. In this case, two regions were fitseparately, the region If<=10mA and the region If>10mA, where If is the LED forward current. The outputcurrent of the Gpcg source is the phototransistor collector current.
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发表于 2021-3-16 10:09
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