# Running several lower-voltage items from a higher-voltage supply

We're running an exhibition that uses lots of 1.5V battery LED torches, which will be on for long periods, and their high-brightness means that using batteries is problematic (continual replacement). I'd like to use a PSU to power them, but don't want to have multiple supplies (or at least, I want to minimise the number of supplies used).

Is there an IC/circuit that can take as input, say, a 12V high-current dc supply, and present as output multiple independent 1.5V sources (each drawing approx 0.7A)?

I can't simply chain the torches I've been given in series, because each one has integral circuitry to run in full/dim/flashing mode according to button pressses, and in series they get very confused...

I even considered buying in my own high-brightness LEDs instead, but the torches (with lenses off) produce very sharp images -- they're being used to project shadow patterns in a gallery -- and so far I haven't been able to find a workable substitute. (It's bad enough, incidentally, trying to find a high-current 1.5V supply!)

I searched for similar questions, but none seemed to match exactly what I was looking for.

• Youu could try a reasonably high power supply and parallel the torches. You may need to get a post-regulator though. – Peter Smith Apr 8 '17 at 15:43
• An exhibition sounds like long wiring to me. Perhaps consider a small custom buck converter (such as, but not necessarily, the TPS62510) for 1.5 V at each one or two LED locations. Alternately, something with higher current capability if more LEDs are nearby each other with short wiring. But either way using a higher voltage distribution system. But perhaps I'm thinking this is large when it's smaller than I'm imagining. So, off-hand, how many of these LED devices are you planning? How much wiring? – jonk Apr 8 '17 at 16:58
• How many is "a lot"? How much do they cost each? Buy more and don't waste your time is my gut-opinion. – Andy aka Apr 8 '17 at 18:42

As Jonk suggested, use buck converters, one for each set of LEDs. Ebay has many such modules for $1-$2 each that you could use. I just searched for "buck module adjustable" and searched by ascending price, and for \$1 inc postage found one that accepts input of 4v-35v and output adjustable 1.25v to 30v. (Maximum input current 3A, I presume this should suffice), it is based on the LM2596 IC.