>--- In oopic@yahoogroups.com, "rtstofer" <rstofer@...> wrote:
> > I also don't have an R board. What regulator is being used? I
> > thought it was rated at 3A or so (heatsinked).
>
> from the ooPIC homepage:
>
>The OOPic-R's 3 voltage regulators are configured so that the logic
>side of the board has a private one-Amp power supply, while the I/O
>has a full five Amps of regulated power,
Those are MAXIMUM current draws under IDEAL conditions and those
conditions are NOT present on the OOPic-R. The tiny logic regulator
may be rated at one amp and the I/O regulator (LM1084) is rated at
five amps, but to supply those currents, they need minimal
differences between their input voltages and their regulated output
voltages and they would need proper heatsinks.
Neither of those regulators have heatsinks on the R board; the only
heat transfer path is through the metal back of the regulators to -
to what? A bit of copper on the circuit board? That part of the
LM1084 regulator is connected to its Vout (+5V), so it's not like
it's even connected to a big honking copper ground plane on the board.
If you ran the LM1084 off a 7.2V battery pack (for example) and tried
to pull 5 amps through it, there would be 11 watts of heat coming off
that regulator (this is basic Ohm's Law and is something every OOPic
user needs to be familiar with)
Where is all that heat going to go when there is no heatsink
present? I will let other elaborate further.
...Andy
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