Supply Voltage Regulators - Nokia Mobile Phones NSE-5 Series Service Manual

PAMS
Technical Documentation

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).
Operating mode
Power off
Power on
Reset
Sleep
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.
Issue 1 07/99
Table 8.
Vref RF REG
Off Off
On On/Off
On Off
VR1 On
On Off
VCOB- VBB
BA
Off Off
On On
On On
On On
NSE–5
System Module
VSIM SIMIF
Off Pull
down
On On/Off
Off Pull
down
On On/Off
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