Nokia Mobile Phones NSE-5 Series, Service Manual, Page: 43 / 327

PAMS
Technical Documentation
NSE–5
System Module
Page 2 – 29
Issue 1 07/99
Supply Voltage Regulators
The heart of the power distrubution is the CCONT. It includes all the
voltage 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 memories, 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 VCOBBA. 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.
The RTC backup is rechargable polyacene battery, which has a capacity
of 50uAh (@3V/2V) The battery is charged from the main battery voltage
by the CHAPS when the main battery voltage is over 3.2V. The charging
current is 200uA (nominal).
Table 8.
Operating mode Vref RF REG VCOB-
BA
VBB VSIM SIMIF
Power off Off Off Off Off Off Pull
down
Power on On On/Off On On On On/Off
Reset On Off
VR1 On On On Off Pull
down
Sleep On Off On On On On/Off
Note: CCONT includes also five additional 2.8V regulators providing power to the RF
section. These regulators can be controlled either by the direct control signals from MAD
or by the RF regulator control register in CCONT which MAD can update. Below are the
listed the MAD control lines and the regulators they are controlling.
–
TxPwr controls VTX regulator (VR5)
–
RxPwr controls VRX regulator (VR2)
–
SynthPwr controls VSYN_1 and VSYN_2 regulators (VR4 and VR3)
–
VCXOPwr controls VXO regulator (VR1)
CCONT generates also a 1.5 V reference voltage VREF to COBBA,
PLUSSA and CRFU. The VREF voltage is also used as a reference to
some of the CCONT A/D converters.
In additon to the above mentioned signals MAD includes also TXP control
signal which goes to PLUSSA power control block and to the power
amplifier. The transmitter power control TXC is led from COBBA to
PLUSSA.