how do i make a constant power load in LTspice?

Question

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 dynamicvariables.maybe it's the question of how to use dynamic variable in LTspice.for example, the idea is:R1 N002 N001 100I1 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.endbut this won't work since i can't just pass V(n002) as a parametersince it's a dynamic variable.is there a way i can fix this?many thanksRen

Charlie E. · Accepted Answer

Ren,Not exactly sure what you want to do, but it sounds like you want aresistance that always consumes the same amount of power, no matterthe voltage across it.  A little odd, but probably doable.In PSpice, you would use a Gvalue part, or a GTable part, where youconnect the sense leads to the output leads.  You then define theoutput (the current through the device) as I(out) = Vsense/PowerLet me know if you have any questions on the actual execution.Charlie

Jim Thompson · Answer

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 infor some fun ;-)                                        ...Jim Thompson-- | James E.Thompson, P.E.                           |    mens     || Analog Innovations, Inc.                         |     et      || Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    || Phoenix, Arizona  85048    Skype: Contacts Only  |             || Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  || E-mail Icon at  |    1962     |              I love to cook with wine     Sometimes I even put it in the food

how do i make a constant power load in LTspice?

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