I do quite like the conversation that this has sparked up... the circuit Ash has drawn up is quite interesting. it seems to be quite thought out. components are cheap though so I don't mind building that if the circuit is functional. it seems Medved has critiques however so I shall stay tuned.

In fact we are talking about chopping may be 20-30% from lamp's power, for 500W load that means just a couple of 0.2 Ohms 100W power resistors in parallel, placed in some well-ventilated area, no big deal... And no messing with any electronics...

If there was really a problem with Apple using some proprietary connector, nobody would buy the phones, problem solved. However, about 30% of the customer base had iphones in the period before the regulation. Apparently they were ok with using iphones with iphone cables

I dont see what was the big problem that was solved by the regulation. "I have a drawer with lots of tangled cables" is a personal problem. "I hate it so lets ban it for everyone" is now everyone's problem, because of the magnitude of precedent of overreach that it sets

The drawer of underwear will be next

@Medved: These are usually MH lamps that are sensitive to burning position. HPS and MV lamps aren't sensitive, because in HPS lamp, the arc is wall stabilized, and in MV lamp, the internal pressure is much lower than in MH lamp, and it is an unsaturated vapor lamp.

HID's are sensitive for internal temperature distribution. You want the cold spot to be at exact temperature to get the vapor pressures you need, but also you want the hot spot to be as cold as possible to not stress the materials that much.
There are many tricks to control that, but the general problem with universal burning is the heat rises, but you don't know where will be the "up". So when designing an universal burning lamp, you need to keep way more margins to accomodate the "up" being anywhere, so you can not go that close to the running optimum.
If you are designing a lamp with strictly restricted burning position, you can count on the exact cooling profile and convection currents, so you can reach way more optimal internal conditions for both higher efficacy, better color stability, longer life, better lumen output stability. Or get away with lower cost design, so cheaper product. Even some lamps are open fixture rated only when operated BU, otherwise they need enclosed fixture, because either the failure modes could be different with different orientation, or the internal protection is effective only for operations at the certain positions.

So yes, if you know your burning position is base up, chances are you can find a better performing (according to your criteria) lamp for BU only. But it is just a chance, not guaranteed, it depends what your main criteria are and what the market offerings are.

I also think this is overcomplicated.
- The gate drive will suffice with barely a mA, the frequency I would not do any faster than about 100Hz. So driving it from a simple two transistor driver should be enough.
- The switching even should not be that fast, with so fast edges, it would create way too high spikes on the wiring inductance. AEC specifies equivalent wiring inductances to anticipate up to 5uH, we are switching 20A in them so if we tolerate about 20..30V overshoots, it means about 2..5us current slopes. With the Gm of about 210S and Cgs of about 24nF it means about 0.6mA gate discharge current. So the 3..5mA should be more than enough. It is asking for a kind of adaptive gate drive: You discharge the gate quickly by up to 20mA via a stronger transistor and diode into the drain and then slowly via the gate series resistor by the 0.6..1mA, so the bulk of the gate charge gets away quickly so won't cause that much delay and once the transistor starts to switch off, the gate current gets reduced so won't create any huge overshoot.

Transients to expect are described in ISO 7637-2.
The really high voltage ones are of an inductive kick origins, so have higher impedance and short time, a series input diode and a good quality electrolytic on the battery input, a pairs of series 100nF ceramics (you need to use two in series on anything without current limitation such as the battery line, as these tend to fail short circuit, which could lead to fire; there are "flex" rated capacitors which you can use just one, but those could be hard to get for "normal civilian"), one pair in front and one behind the diode is usually enough.
Then there is the "load dump" (simulates disconnection of a loaded and fully biased alternator, mainly happening when battery is failing by first shorting a cell, overcharging the rest and then internal connection breaking due to severe overcharge), which means the thing should tolerate 40V (the alternator is expected to clamp the voltage between 28..40V under this condition) on the battery input for at least a second (the time it may take for the field excitation to dissipate).
And then of course the voltage excursions like starting undervoltage (may lead to transistor damage because of insufficient gate drive voltage under load) down to 3.5V, "jump start" overvoltages up to 28V for a minute or so, plus the "slow battery charge/discharge" (voltage ramp down/up 12V to 0 and back over a few hours), these are asking for over and undervoltage shut downs (the overvoltage won't be threatening the electronics that much, as it will the lamps). Normal range is normally specified as 8..16V, where it is supposed to work normally. So I would put the undervoltage to about 7.5V and overvoltage to 18V.

That's how many really old switches were done. Incandescent lamps dont make too much arcing, so while there is wear on the contacts, they are just big enough to last 120 years and more. The sweeping motion guarantees clean contact point every time

Here many of the devices made in the 90s were still the good ones, that actually can last

USB-C is pretty much OK for mobile phones. Using as a do-it-all including power external connection for laptops may be not so justified...

From what I know US switches and sockets are basically made to be disposable, it's just a single piece you can't open without getting destructive. Same with new european things really, it's not made to last.

We're actively using early 1900s material at home and it all works like new, I rewired the house some years ago and also took the time to restore the sockets and switches, they're porcelain pieces with brass contacts inside, so making them tight again only took a little bending using pliers, I also re-polished everything to remove the 120 years of grime they had on them. The switches don't have a clicky spring, it's just a contact that slides over the other, it works like a valve.

I did it because of two things, one to keep the decor period accurate, cheap plastic switches would honestly ruin it, and second because there's no way to install something new without smashing the walls to get new boxes in place, the existing ones aren't compatible with new things, the plastic switches simply don't fit in any way.

You *can* use old things, just not 1990s old. 

The USB-C is not because of phone makers wanted to. They were forced to use a common connector by the European Union, include Apple. Even when Apple was against that. Not respecting that would mean simply a sales ban in the EU.