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What are some tips for modeling optocouplers for Pspice?
& n7 x) N. j# V) ?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.: X6 [8 X1 N- d8 B
In the case of the optocoupler，you need to create a model for a LED input，and also for a single BJTphototransistor output optocoupler., r4 {) X! x6 F) B% U
1.LED
5 o: @1 ~ H- X8 ~4 i: 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.% a0 z8 l9 A# d1 ]# ?, e- p x
2.CTR curve fit
7 @8 a0 c& g! f2 [Use Mathcad or Excel to fit the CTR curve to a polynomial. A polynomial which may work is of the formA*exp(B+Cx).
& Y% {( z& J+ F/ P6 L+ s& _* {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.- k& F; W ~* @5 v, F
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发表于 2021-3-16 10:09
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