Standardization of DC power supplies (chargers) for CE

[whit3rd]

The makers should be allowed to build whatever they want. It's their product
they are offering for sale, their power source they've intimately specified
and in turn I can choose to buy it or not.

True, they should be ALLOWED to do any silly irreproducible
thing they want. But, not ENCOURAGED.

I remember the original USB connector was designed by a committee of
(software?) suppliers as  'standard'. Seems we're now up at about six
varieties.

The standard only relates to three, the A and B and one 'mini'.

I find seven (five different mini connectors, no less)
represented in my box o' cables. Back in the
old days, SCSI connectors numbered twenty variants,
and it was not pleasant. Four standard connectors
for SCSI were eventually specified, and things got... better.

For USB, I predict another three years of chaos. Has anyone
seen the USB-3 connectors with fiber optic elements?

 

[Eeyore]

True, they should be ALLOWED to do any silly irreproducible
thing they want. But, not ENCOURAGED.

That's fair. Some external PSUs ned to provide several voltages but these are
naturally excluded by means of the connector with confusion with other types.

Graham

 

[Theo Markettos]

Is there actually any existing ready-to-use standard that could be
mandated stem the current bewildering variety of connectors and
specifications for DC power supplies ("chargers") for digital
consumer-electronics devices (phones, cameras, PDAs, printers, etc.)?

Well there is one standard that's almost universally adhered to, but it
might not be practical... it's the cigar lighter plug for cars. 12-18V DC
at as many amps as you can take before the fuse blows.

This is clearly an area that needs some work. If there really are
good reasons to have different voltages and maximum currents
provided by the supply (9 V, 12 V, 15 V; 2 A, 3 A, 5 A),
then perhaps a little negotiation protocol a la power-over-ethernet
(48 V) or USB (5 V) would be the right approach? It might add a
dollar or two to the cost of the individual charger/supply, but would
lead overall to enormous savings by reducing the number of
chargers required in a household.

How about an alternative solution... all devices should include their own
power conditioning module/circuit. You throw them N volts AC at
'sufficient' current, where N is within some range (maybe 3-18V) and it's up
to them to rectify and regulate this to whatever's wanted internally. The
wall-wart is just a transformer and a fuse. If you want the wall-wart to be
an efficient SMPSU, just feed DC into the low voltage AC input. (The
rectifier diodes will have to be specced for this). There would probably
need to be some kind of brownout detection in the regulator circuit.

This isn't too different from what happens already, it's mostly a
documentation change. Rather than saying '9V DC, 1A' on some input that
already has reverse protection and an internal switching regulator, just
specify it to take all comers.

The really cheap stuff has a transformer-in-a-box and some bad linear
regulation. I'm not sure of the best approach for this - make switching
modules that are cheap enough to put inside?

Theo