Backup Battery; Normal And Extreme Voltages; Power Key And System Power-Up - Nokia RM-235 Service Manual

RM-235
System module and user interface
• BSI (Battery size indication)
• GND (Battery ground)
Charging
This phone is charged through the smaller Nokia standard interface (2.0 mm plug).
Charging is controlled by energy management, and external components are needed to protect the baseband
module against EMC, reverse polarity and transient frequency deviation.

Backup battery

When the main battery is not attached EM ASIC (N2200) goes in backup mode using back-up battery that
supplies voltage to RTC in EM ASIC (N2200).

Normal and extreme voltages

Energy management is mainly carried out in the two Application Specific Integrated Circuits (ASICs) BETTY
and AVILMA. These two circuits contains a number of regulators. In addition there are some external
regulators too.
In the table below normal and extreme voltages are shown when a BL-5F S-pack battery is used.
Voltage
Nominal voltage
Lower extreme voltage
Higher extreme voltage
(fast charging)
Vmstr+
Vmstr-
Sw shutdown
Sw shutdown
Vcoff+
Vcoff-

Power key and system power-up

When the battery is placed in the phone the power key circuits are energized. When the power key is pressed,
the system boots up (if an adequate battery voltage is present).
Power down can be initiated by pressing the power key again (the system is powered down with the aid of
SW). The power key is connected to EM ASIC N2200 (AVILMA) via PWRONX signal.
Issue 1
Table 13 Nominal voltages
Voltage [V]
General Conditions
3.700
3.145
4.230
HW Shutdown Voltages
2.1 ± 0.1
1.9 ± 0.1
SW Shutdown Voltages
3.1
3.2
Min Operating Voltage
2.9 ± 0.1
2.6 ± 0.1
COMPANY CONFIDENTIAL
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Condition
Off to on
On to off
In call
In idle
Off to on
On to off
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