High Power TL432?

Why not just constant current to resistors? The power transistors can handle the current, if i keep Vec low.

I often add a resistor on the input side of a linear regulator, to gobble up maybe half the max dissipation.

On a sunny day (Fri, 26 Aug 2022 13:43:29 -0700 (PDT)) it happened Ed Lee snipped-for-privacy@gmail.com wrote in snipped-for-privacy@googlegroups.com:

Why not use a reverse converter to feed back power to the source? :-)

Anyways, in the old days as over-voltage protection : voltage sensor driving a thyristor to short the output and primary fuse. That was the classic protection against the series switching transistor failing.

Same problem as lacking storage for Nat. Gas in another thread. For example, Russia is burning million dollars worth of Nat. Gas daily near the Finland border, because they have nowhere to store it. BTW, they also burn rubles for us to see by pumping to the west rather than burning at the source.

The power sources are 180Wh to 210Wh (300Wh when new) batteries. We need to remove energy from it, cannot pump it back. I am just burning a few cents.

;-(

We don't want to short the power source and explode.

The 200W Tarlington and 300W Qarlington are over-speced to avoid failure. In reality, i don't expect over 100W.

The power spec on the part assumes an infinite heat sink - on real heat sinks they get hot enough to fail at lower power dissipations.

You have to add up the thermal resistances from junction to case, from case to heat sink, and from heat sink to ambient, work out your maximum ambient temperature and make sure that the junction never gets too hot. With big transistors you find yourself stuck with big heat sinks and a fan built into the heat sink assembly. It gets nasty. Even nastier when it's an afterthought, and there's no room for a big enough heat sink let alone the fan, as happens when you have to rescue other people's half-baked or over-hasty design efforts.

I figure around 1/2 for the transistor and 1/2 for the resistor. TO-3 is rated for around 100W at 200C (0.6 W/C) with reasonable heat sink.

2N6287: 0.9W/C 160W 200C max. A heat sink with 2x to 3x surface area should bring it down to 100C to 120C.