zalozni baterka k LPC2378

[Ivo Strasil]

Hodne tyhle brouky nemam rad... viz vysek z erraty niz, taky jsem to 
musel resit.

Hezky den,
Ivos

VBAT.1: Increased power consumption on VBAT when VBAT is
powered before the 3.3 V supply used by rest of the device
Introduction:
The device has a VBAT pin which provides power only to the RTC and 
Battery RAM.
VBAT can be connected to a battery or the same 3.3 V supply used by rest 
of the device
(VDD(3V3) pin, VDD(DCDC)(3V3) pin).
Problem:
If VBAT is powered before the 3.3 V supply, VBAT is unable to source the 
start-up current
required for the Battery RAM. Therefore, power consumption on the VBAT 
pin will be high
and will remain high until 3.3 V supply is powered up. Once 3.3 V supply 
is powered up,
power consumption on the VBAT pin will reduce to normal and subsequent 
power cycle
on the 3.3 V supply will not cause an increased power consumption on the 
VBAT pin.
Work-around:
Provide 3.3 V supply used by rest of the device first and then provide 
VBAT voltage.

Dne 24.3.2011 14:31, Fanda Kopriva napsal(a):
> Dobry den
> Kdyz pripojim 3.3V zalozni baterku k RTC v LPC2378 tece z ni proud 0.5mA
> az do zapnuti hlavniho zdroje.
> Po resetu se inicializuje RTC a proud klesne na popsanych 20uA.Po
> vypnuti hlavniho zdroje potom zustava tento proud.
> Zda se ,ze se baterka neda vlozit bez nasledneho zapnuti ,protoze by se
> vybila.
> Nedelam neco blbe?Zatim jsem k tomu nic nenasel.
> Fanda
>
>
>
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