zalozni baterka k LPC2378

Fanda Kopriva info na elektronikavyvoj.cz
Pátek Březen 25 11:27:19 CET 2011


Diky
   Fanda
Dne 25.3.2011 8:40, Ivo Strasil napsal(a):
> 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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