AMC7135's in series

Been thinking about the above set up. Has anyone tried it with 10 NiMh cells? Im thinking the Vin may be just a little high for the 7135's.

So what would happen if I seriesed 3 3x7135 boards? would one board end up doing all the work or would they balance out?

hmm...they are usually paralleled by convention to increase current output...serializing regulators might lead to an epic failure if one 7135 can't deliver enough power to the successive board

dunno, we'll let the experts chime in

Me no expert at all....These are best run off a single LIPO batt as they are very eff when close to VF...don't think series would work...

TaskLED has some great driver for the app you are doing...

the circuit you show in the pic with parallel drivers will work as the VF is dropped by the P7's in seires with the driver input...as for 10 nimh, would still work but be less efficient...( in theory, have not tried it) & I could be wrong but I am sure I saw a post that the circuit in the pic works...

K

Packhorse said:

So what would happen if I seriesed 3 3x7135 boards? would one board end up doing all the work or would they balance out?

Click to expand...

The last 7135 IC will do all the work. Previous 7135 IC will just drive the next one.

Packhorse said:

Been thinking about the above set up. Has anyone tried it with 10 NiMh cells? Im thinking the Vin may be just a little high for the 7135's.

Click to expand...

It depends on the Vf of your leds. As long as you keep the voltage over the 7135 below 6V you will be fine. So for 12V you need to have a VF of at least 3V which most leds have. I'm using this setup with 3 li-ions which give 12.6V fully charged. No problem at all.

If you are planning for a P7: NiMhs would have a hard time to deliver 2.8A. It wouldn't work very well. But for XR-Es or SSC P4 you should be fine. the 7135 cirquits are fairly robust and if you heatsink them they will hadnle quite high voltage.

and.. One is enough

gillestugan, what's a good way to heatsink these? Would it work to just smear some thermal adhesive on the top (where the ICs are) and press against a heatsink?

Thats What I have done in the past. Seems to work well.