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What are some tips for modeling optocouplers for Pspice?" h0 w9 J0 U5 h- t7 t- b
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.. _) h8 [/ A9 m1 q' n8 y! v
In 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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; i! G" o6 }7 gTo 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.
! Q- A$ X- q* }" z2.CTR curve fit
" C' Q4 N) b! K% ?Use Mathcad or Excel to fit the CTR curve to a polynomial. A polynomial which may work is of the formA*exp(B+Cx).
! Z2 N, s2 b8 u7 Q3 `- B3 aIn 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.6 |6 q& u7 L0 w( U, J+ N( O$ H
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发表于 2021-3-16 10:09
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