User Guide

PAMS
Technical Documentation
NSE–8/9
System Module
Page 2– 46
Issue 1 07/99
The schottky diode, V101 is only conducting during the small time when
power FET conduction inside V105 is shifted.
The resistors R131 and R132 forms together with the transistor V109a
and R134 a circuit which will shut down the switcher when the battery
voltage reaches 1.4V in order not to drain the battery below a limit of
insufficient current capability. Additionally this circuit generates via V109b
an interrupt to the MAD2PR1 SIMCardDetX, when the battery is removed,
in order to insure the proper shutdown sequence of the SIM card.
Baseband supplies, CCONT
The heart of the Baseband power distribution 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 supply. The Baseband regulator is active always when the
phone is powered on. The VBB Baseband regulator feeds MAD2PR1,
memories, COBBA_GJP digital parts and the LCD driver.
Additionally the NSE–8/9 is prepared for a separate supply, Vcore for the
core logic in the future version of MAD2PR1 C07 process. The core
supply can be enabled by inserting R315 and removing R314. The SW
identifies the MAD2PR1 type (to be C07) and commands the CCONT core
regulator accordingly.
The COBBA_GJP analog parts are powered from a dedicated 2.8V
supply, Vcobba, which can be turned off in sleep mode.
The CCONT contains a real time clock function, which internally is
powered from the switcher output. When the phone is powered off the
switcher continues to operate at it’s lowest output voltage level, thus still
supplying the RTC. When the battery SW cutoff voltage is reached the
switcher continues to operate at least 24h, providing supply for the RTC.
In case the main battery is removed the RTC is powered by the output
capacitors on the switcher until they are drained and the RTC loses it’s
timing. The time must be set again upon power on.
Table 20. Regulator activity in different operating modes
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
VXO On
On On Off Pull
down
Sleep On Off On On On On/Off