Hi Christian,
On Tue, Jul 10, 2012 at 07:04:35PM +0200, Christian Daniel -- maintech GmbH wrote:
We violate the 100mA limit by a small amount. FPGA and
E4K can be
switched off and the ADC doesn't consume much when no clock is
applied. I don't see a problem here - at least after we fixed the
power sequence to stop it from using the full 400mA directly on power
up. Also a diode for external power supply is on the board. But yes -
it will not be USB certified. But so far this is not a real-world problem.
Actually, now that you're doing a re-design for the SSC -> EBI change,
it might be an idea to make the oscillator power supply switchable and
controlled by a GPIO from the SAM3U or FPGA. At that point, there's no
problem booting at < 100mA.
I wouldn't expect a small low-Rds_on mosefet switch to cause any problem
for the oscillator, especially since it's constant current/power...
Regards,
Harald
--
- Harald Welte <laforge(a)gnumonks.org>
http://laforge.gnumonks.org/
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