Normal And Extreme Voltages; Power Key And System Power-Up; Modes Of Operation - Nokia n81 Service Manual

RM-179; RM-223
System Module and User Interface

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 BP-6MT 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.

Modes of operation

Mode
NO_SUPPLY (dead) mode means that the main battery is not present or its voltage is too low (below
N2200 AVILMA master reset threshold) and that the back-up battery voltage is too low.
BACK_UP The main battery is not present or its voltage is too low but back-up battery voltage is
adequate and the 32 kHz oscillator is running (RTC is on).
PWR_OFF In this mode (warm), the main battery is present and its voltage is over N2300 BETTY
master reset threshold. All regulators are disabled, PurX is on low state, the RTC is on
and the oscillator is on. PWR_OFF (cold) mode is almost the same as PWR_OFF (warm),
but the RTC and the oscillator are off.
Issue 1
Table 7 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
3.25
3.25
Min Operating Voltage
2.9 ± 0.1
2.6 ± 0.1
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Condition
Off to on
On to off
In call
In idle
Off to on
On to off
Description
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