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Power two mainboard


#1

Hi,
in a project I should use 2 mainboard, cobra 2 as master and a cerberus as slave.

I would like to know if it would be possible to power a cerberus + related modules (eg cellular module etc.) using the 5v taken from a socket cobra 2 (i burns the cobra 2?), or i should use a Power Extender Module?

Thanks
Luca


#2

maximum current that will go through the DP or SP is set to 800ma if I remember correctly, so using one to power TWO Boards with regular modules is possible, just remember you can never have TWO red board (power) boards plugged into one board…
now with that said, as for your setup you will have to find out the amount of current required for your modules, so my recommendation is to use the power extender if you have one… or two separate Power modules…

by the way using one Red Module to power everything might seem to work at first but there are no guarantees that it will perform correctly meaning if your code start to behave in a weird way start by updating your power setup…

oh and to power two boards with one module just connect any two sockets from the two boards…

cheers,
Jay.


#3

The cobra 2 schematic shows the input power is handled by a mic4680, a 200khz switching regulator capable of outputting 5v 1.3A. The 3v3 is then put thru a lm1117 jellybean linear regulator. So if you have no more than 1.3A requirement you might be ok… but you will need 3v3 to power the Cerberus so be careful how much power you need as a single lm1117 at say its max of 800ma will get hot.

If it was me, I think you need a custom, higher power solution. The power extender isn’t any different from a capability perspective except it isolates the consumption sources, but if you had a single 12v source of sufficient capacity inputting into both the cobra2 and the power extender, you essentially get 1.6A of 3v3 power, but its still effectively 2 power supplies running. In my mind, one major regulator like the Micrel, then two separate lm1117s for each mainboard is workable (although on the upper limit of the Micrel’s limits). Thinking about it, using a DP module for Cerberus and sending 5v only, not 3v3, to the cobra, would possibly work…