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What are some tips for modeling optocouplers for Pspice?
. j/ f9 }) D1 v4 _% k2 j" |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., H( p' y( V* h0 M
In the case of the optocoupler，you need to create a model for a LED input，and also for a single BJTphototransistor output optocoupler.3 m1 X f2 u8 | A/ d# x: ?: h
1.LED! o+ Y0 i6 F0 r
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.1 Z+ S! n. T0 W2 ]+ N1 [ `
2.CTR curve fit
2 z; t2 e. @9 a5 k: e, R; G( A4 YUse Mathcad or Excel to fit the CTR curve to a polynomial. A polynomial which may work is of the formA*exp(B+Cx).# x. G: E" K( k! K( s3 J
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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