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Consider a SMPS with a control loop that uses an analog multiplier to control its output voltage in order to maintain a constant power output. I am trying to figure out some of the applications where this operating mode is more beneficial than constant voltage or constant current.

The only scenarios I have been able to come up with are for resistive heaters. Does anyone know of any other applications?

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    \$\begingroup\$ Hm, I'm not willing to be a judge of that, but: technically, there's no "right" or "wrong" answer to any question that is "do you know other examples", so that puts this a bit on the edge of the kind of questions you can ask here. \$\endgroup\$ Commented Jun 1, 2021 at 16:17
  • \$\begingroup\$ similar to heaters but more broadly, potential use for any process that's limited by thermal dissipation \$\endgroup\$
    – Pete W
    Commented Jun 1, 2021 at 16:42
  • \$\begingroup\$ Related: electronics.stackexchange.com/questions/350405/… \$\endgroup\$
    – Voltage Spike
    Commented Jun 1, 2021 at 17:26
  • \$\begingroup\$ @VoltageSpike I don't have a problem with actually making the constant power source, just some applications for its use. \$\endgroup\$
    – Stiddily
    Commented Jun 1, 2021 at 17:45
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    \$\begingroup\$ @Agent_L the CP mode of the supplies in question is already there. Mostly used for paralleling when the PFC in front can't support the full load of everything it is powering. More of a marketing question that anything \$\endgroup\$
    – Stiddily
    Commented Jun 2, 2021 at 11:44

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One other application I'm aware of is in electrosurgery. There are certain modes where you want to deliver constant power to the scalpel so that as tissue impedance changes the power delivered and "feel" of the scalpel don't change.

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  • \$\begingroup\$ When you say "deliver constant power to the scalpel" I assume you are referring to some form of actuator that controls the movement? \$\endgroup\$
    – Stiddily
    Commented Jun 1, 2021 at 17:51
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    \$\begingroup\$ @Stiddily No, the scalpel is a hand-held instrument with a flat blade at the end that the surgeon uses to cut and/or cauterize. \$\endgroup\$
    – John D
    Commented Jun 1, 2021 at 18:05
  • \$\begingroup\$ ah, I was picturing a robo-surgeon of some kind. I hadn't heard of electrosurgery before. Very interesting. \$\endgroup\$
    – Stiddily
    Commented Jun 2, 2021 at 11:51
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One application would be peliters, it would be nice to control the power to the device. Minus the resistive heating it's the power that determines how much cooling/heating the peltier gets.

When you start talking about controlling power, it usually means there is a V/I curve that is not constant like a resistive load.

Solar panels, peliters, diodes and many other devices that have a non-constant relationship between V/I can require more than just voltage control, and also either need constant current or both voltage and constant current control. What this usually ends up being is voltage control with a way to measure the current and control the power with PWM.

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Heaters. Electric motors e.g. for pumps.

I personally also know this from sputter supplies. As the ablation rate depends mainly on the power, you want to keep power constant. The voltage can fluctuate quite a bit though when vacuum conditions change slightly, so it is not enough to maintain voltage or current.

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