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What are some tips for modeling optocouplers for Pspice?& W1 X; Y, g" f( a9 Q8 X3 L
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.5 @7 w1 f3 X; `0 C2 C( 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.
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! _7 I8 D) r; X4 B9 g6 O5 m! uTo 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.) z }# y' m( ~) \% J
2.CTR curve fit, ?/ I" e v- D- s; }
Use Mathcad or Excel to fit the CTR curve to a polynomial. A polynomial which may work is of the formA*exp(B+Cx).6 p# O, S) i& j! u( { q3 X: n
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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