Battery Temperature; Supply Voltage Regulators - Nokia NSE–3 SERIES Service Manual

PAMS
Technical Documentation

Battery Temperature

The battery temperature is measured with a NTC inside the battery pack.
The BTEMP line inside transceiver has a 100k pullup to VREF. The MCU
can calculate the battery temperature by reading the BTEMP line DC–
voltage level with a CCONT (N100) A/D–converter.
BATTERY

Supply Voltage Regulators

The heart of the power distrubution is the CCONT. It includes all the volt-
age regulators and feeds the power to the whole system. The baseband
digital parts are powered from the VBB regulator which provides 2.8V
baseband supply. The baseband regulator is active always when the
phone is powered on. The VBB baseband regulator feeds MAD and me-
mories, COBBA digital parts and the LCD driver in the UI section. There is
a separate regulator for a SIM card. The regulator is selectable between
3V and 5V and controlled by the SIMPwr line from MAD to CCONT. The
COBBA analog parts are powered from a dedicated 2.8V supply VCOB-
BA. The CCONT supplies also 5V for RF and for flash VPP. The CCONT
contains a real time clock function, which is powered from a RTC backup
when the main battery is disconnected.
Original 11/97
BVOLT
BSI
BTEMP
R
T
1k
NTC
BGND
System Module
TRANSCEIVER
VREF
100k
10k
BTEMP
1k
10n
VibraPWM
MCUGenIO4
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NSE–3
CCONT
MAD