User`s guide

6
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32 Analo
g
Behavioral Modelin
g
EMULT, GMULT, ESUM, and GSUM
The EMULT and GMULT parts provide output which is based
on the product of two input sources. The ESUM and GSUM
parts provide output which is based on the sum of two input
sources. The complete transfer function may also include other
mathematical expressions.
Example 1
Consider the device in Figure 6-17. This device computes the
instantaneous power by multiplying the voltage across pins
%IN+ and %IN- by the current through VSENSE. This device’s
behavior is built-in to the TEMPLATE attribute as follows
(appears on one line):
TEMPLATE=E^@REFDES %OUT+ %OUT- VALUE {V(%IN1+,%IN1-)
*V(%IN2+,%IN2-)}
You can use the symbol editor to change the characteristics of
the template to accommodate additional mathematical
functions, or to change the nature of the transfer function itself.
For example, you may want to create a voltage divider, rather
than a multiplier. This is illustrated in the following example.
Example 2
Consider the device in Figure 6-18.
Fi
g
ure 6-18
GMULT Part Example
With this device, the output is a current is equal to the ratio of
the voltages at input pins 1 and input pins 2. If V(%IN2+, %IN2-
) = 0, the output depends upon V(%IN1+, %IN1-) as follows:
if V(%IN1+, %IN1-) = 0, output = 0
if V(%IN1+, %IN1-) > 0, output = MAXREAL
if V(%IN1+, %IN1-) < 0, output = -MAXREAL
Fi
g
ure 6-17
EMULT Part
Example