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how do i make a constant power load in LTspice?

Hi there,

this group looks pretty spamed, but i'll try my luck.

does any one knows how to make a constant power load in the LTspice?

i've tried a few things but they all involving using dynamic variables.

maybe it's the question of how to use dynamic variable in LTspice.

for example, the idea is:

R1 N002 N001 100 I1 N002 0 {current(p,V(n002))} V1 N001 0 10 Rser=1 .param p=10 .func current(power,voltage) {power/voltage} .tran 0 1m 0 1u startup .backanno .end

but this won't work since i can't just pass V(n002) as a parameter since it's a dynamic variable.

is there a way i can fix this?

many thanks

Ren

Reply to
tomrei
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Ren, Not exactly sure what you want to do, but it sounds like you want a resistance that always consumes the same amount of power, no matter the voltage across it. A little odd, but probably doable.

In PSpice, you would use a Gvalue part, or a GTable part, where you connect the sense leads to the output leads. You then define the output (the current through the device) as I(out) = Vsense/Power

Let me know if you have any questions on the actual execution.

Charlie

Reply to
Charlie E.

If you don't bound the max current/max voltage, it'll not converge.

The OP is probably testing a power supply fold-back limit. He's in for some fun ;-)

...Jim Thompson

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| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

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