[Arm-netbook] EOMA68 Power Specifications

[Luke Kenneth Casson Leighton]

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crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68


On Tue, Aug 30, 2016 at 10:39 PM, Joseph Honold <mozzwald at gmail.com> wrote:


> Seems like there should be a minimum power requirement that all cpu cards and devices must meet.

 okay - so you used the word "devices" which is not part of EOMA68
terminology.  sorry i missed this, so didn't understand the question.

 *from the perspective of the EOMA68 Cards* the *MAXIMUM* that they
are permitted to use is 1.0A @ 5.0v

 therefore...

 *from the perspective of EOMA68 ***HOUSINGS*** .... * the *MINIMUM*
that they must provide is: 1.0A @ 5.0v

 above exactly 1.0A @ 5.0v, housings are ***REQUIRED*** to cut power
without warning.


> What happens if someone makes an ultra low power cpu card that peaks at 200mA and I design my device/housing to meet that 200mA but not higher and I try to plug the A20 card into it? It will be unstable or not work at all.

 okay now you're using the word "housing" so it's clear.

 if you do not provide up to 1.0A that will not be compliant with the
EOMA68 standard.  you will risk having electronics burned out and
possibly causing a fire hazard, potentially causing serious injury,
destruction of property or death.

 please don't do that.  please make sure that you comply with the
standard - make sure that the Housing provides up to the required 1.0A
@ 5.0V and has the required "over-current" protection.

 you can use something like a SY6280 or similar IC which provides
over-current, short-circuit protection and over-temperature
protection.  the datasheet says that the SY6280 also discharges the
output capacitor during shutdown, which is quite important.


>>> What is the A20 cpu card power consumption (average/peak)?
>>
>>  peak is around 3.5 watts.
>
> So, the minimum requirement for the A20 cpu card is ~700mA peak?

 about that, yeah.  but please do not rely on that as a design guide
for selection of components.  please ensure that you select the
correct IC which covers all eventualities.

l.