independent current source with set of conditional equations

[rob_xx17]

hello,

I'm trying to build this customized block. it has a bunch of fixed value elements (2 resistors and 2 capacitors) and a current source. the current source needs to have a value that's based on a conditional expression expression:

Id = something; for Vgs < something, Vds < something

      something else; for Vgs < something, Vds > something

      something else; for Vgs > something

I have the equations and I have all of the parameters, but I have no idea how to implement the conditional statements for the current source. I'm not even sure where to start. thank you very much for any help.

r.

[_user32]

rob_xx17,

These are Analog Behavioral Model sources, for current, ABM_Current, and also ABM_Voltage for voltage.   They are very useful to set up a series of conditions (relative to other values within the circuit) to generate appropriate controlled current and voltages.

The ABM sources can be found in Master Database -> Sources -> CONTROLLED_CURRENT_SOURCES  (or CONTROLLED_VOLTAGE_SOURCES).

Here is an example of using them with a nested if/then conditional.

In this example I1 is depended on the voltage at net(1) - which is simply V1.

So in this example, for I1 you have 3 states (dependent on V1):

a) V1 > 4V, I1 = 1 (Amp)

b) V1 <= 2.5V, I1 = 0 (Amp)

c) V1 greater than 2.5V and 4V or less (inclusive), I1 = 0.1 * V1 (Amp)

Here is a look at the behavior of I1 as V1 varies from 0 - 5V and back from 5 to 0....

To specify a single ended voltage referenced to ground net(0), you just specify V(netname).  

To specify a differential voltage, you would state V(net, net2)...

Regards,

Pat Noonan

National Instruments