Peltier effect heat pump ? aka Peltier coolers.
Stick a current through it, one side cools the other side heats up.
Comes in marshmallow size too.
Not sure of cost though. GBP30 for 55W ??
Various wattage too.
i've seen something akin to an isolated FET driver using a pulse transformer with appropriate turns ratio that may do this. Pulse on to draw it and 1V to keep it there. It might depend on how quickly the supply comes up to generate the 'ON' pulse. How long the pulse needs to be there and so on...
For high currents I have used several forward biased diodes to create small-ish drops. nb Vf will change for different currents - check data sheet graphs
Diodes connected in series - to be clear ;-)