Got an unusual one - I have a lot of "stuff" out there designed for 48VDC. It can tolerate 51VDC continuous, and will crowbar at 52V (app 1 sec) - all fine.
So everyone I deal with is moving to a SYSTEM 48V BUS and doing away with converters, both 12V etc up and 240VAC down. Some of these BUSes are 1,000s Amps. They are also directly connecting to 48V vehicles - with 4x12V batteries - with flat > Full alternator charging. PoE cameras, switches etc etc. This now sees anything from 48-56VDC on the BUS. Re-designing 100s devices is not an option.
I could just "Insert" a string of high current diodes in the DC line (in a nice 2 terminal Al case), for 6-7V drop, and call it quits, but that is a lot of often UN-necessary heat and loss, especially for installs that are running at 48-51V.
I need to have that much higher Vloss, as damn diodes Vf vary from 0.5+V at 0.1A > 2.0V at 10+A. When the systems are in idle, they draw very little current, and once the crowbar fires, they'd have to restart the machinery, some of it is huge :-)
I had planned on a series of diodes with "taps", so the Installer could check the system voltage and select the appropriate "drop-out voltage" required ... perfect
Anyone know of a device with a junction that has ~ 0.6-2.0V loss at all currents? Even a zener assisted PNP varies too much .. or other ideas? Has to be DC line only and simple.