Nokia NSE-3 SERIES, Service Manual

Page: 32 / 217

PAMS
Technical Documentation
NSE–3
System Module
Original 11/97
Page 3 – 26
Power up with a charger
When the charger is connected CCONT will switch on the CCONT digital
voltage as soon as the battery voltage exeeds 3.0V. The reset for
CCONT’s digital parts is released when the operating voltage is stabilized
( 50 us from switching on the voltages). Operating voltage for VCXO is
also switched on. The counter in CCONT digital section will keep MAD in
reset for 62 ms (PURX) to make sure that the clock provided by VCXO is
stable. After this delay MAD reset is relased, and VCXO –control
(SLEEPX) is given to MAD. The diagram assumes empty battery, but the
situation would be the same with full battery:
When the phone is powered up with an empty battery pack using the
standard charger, the charger may not supply enough current for stan-
dard powerup procedure and the powerup must be delayed.
Power Up With The Power Switch (PWRONX)
When the power on switch is pressed the PWRONX signal will go low.
CCONT will switch on the CCONT digital section and VCXO as was the
case with the charger driven power up. If PWRONX is low when the 64
ms delay expires, PURX is released and SLEEPX control goes to MAD. If
PWRONX is not low when 64 ms expires, PURX will not be released, and
CCONT will go to power off ( digital section will send power off signal to
analog parts)
VBB (2.8V)
CCPURX
PURX
Vchar
1 2 3
1:Power switch pressed ==> Digital voltages on in CCONT (VBB)
2: CCONT digital reset released. VCXO turned on
3: 62 ms delay to see if power switch is still pressed.
VR1,VR6
SLEEPX
PWRONX