standby current - LPC213x and LPC214x family

Started by Gazelle July 29, 2005
Dear Philips people,
Dear Forum,
Has someone experience with the standby current of the LPC213x and LPC214x derivates
and can tell me what to expect what to expect when the core is in sleep mode with and without the RTC running.
Is there also possibility to wake up the core with a timer running in the background and what would be the expected
stand-by current in that "sleep mode" ? Are there graphs available ?
The aim is to build a small POS printer on ZigBee and power management with a portable device is always an issue.

Thanks for all technical input !

Have a nice weekend

:-)

Michel



An Engineer's Guide to the LPC2100 Series

Hi Michel,

for the RTC running the current draw from Vbat is between 15 and 20
uAs for the LPC2138, don't have numbers for the LPC2148 yet but should
eb very similar.

In sleep mode (power down mode) with buffering the entire memory of
the LPC2138, we saw around 50 uAs from Vdd. Be aware that the status
of the port pins is retained and some ports have a pull-up build in.
If you drive a "0" to a port pin with pull-up, your power down current
goes up a lot!

Another thing we saw, when the LPC2138 get's hot (e.g. dark box in
plain sunlight, guess 70-90C) the power down current can go up to a
couple hundred microamps, but I heard this is true for all the new ARM
devices because of the small processes they are built with.

I guess that is why the max power down current is specified so much
higher than what we measure, because it has to cover the whole
temperature range to 85C

Cheers, Bob

--- In lpc2000@lpc2..., "Gazelle" <michel.heuts@t...> wrote:
> Dear Philips people,
> Dear Forum,
> Has someone experience with the
standby current of the LPC213x and LPC214x derivates
> and can tell me what to expect what to expect when the core is in
sleep mode with and without the RTC running.
> Is there also possibility to wake up the core with a timer running
in the background and what would be the expected
> stand-by current in that "sleep mode" ? Are there graphs available ?
> The aim is to build a small POS printer on ZigBee and power
management with a portable device is always an issue.
>
> Thanks for all technical input !
>
> Have a nice weekend
>
> :-)
>
> Michel


I have been reaching about 90 uA for both battery and supply

Yes you can wake from sleep via the RTC as well as external interrupts - this works well. The uarts dont work
in power down but you can use a transition on uart0 to wake the processor. switch port to interrupt mode - power down and wait for transition - swich port back to uart - watch for malformed characters in the Uart.
The processor takes about 30 usec to wake up. The wake up process consumption can use more that the processing you do while awake. Expect about 110 uA if waking every second

as bob says: watch for pullups in some pins - these can hog power if your not carfull

see my postinin the files section.

Owen

Has someone experience with the standby current of the LPC213x and LPC214x derivates
and can tell me what to expect what to expect when the core is in sleep mode with and without the RTC running.
Is there also possibility to wake up the core with a timer running in the background and what would be the expected
stand-by current in that "sleep mode" ? Are there graphs available ?
The aim is to build a small POS printer on ZigBee and power management with a portable device is always an issue.