Nokia 616 Service Manual page 214

TFE-4/RV-1
TF4 Technical Information
Backup
In BACK_UP mode the main battery is either disconnected or has a low voltage level
(VBAT < V
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clock is disabled in BACK_UP mode. Instead the unregulated backup battery voltage
VBACK supplies the output of the VRTC. All other regulators are disabled and the phone
has no functionality.
The UEM will recover from BACK_UP mode into RESET mode if VBAT rises above V
Power off
In order for the UEM to be in PWR_OFF mode, it must have supply voltage (VBAT >
V ).
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The regulator VRTC is enabled and supplying the RTC within the UEM. The UEM will enter
RESET mode after a 20 ms delay whenever one of the below listed conditions is logically
true:
• The power button is activated
• Charger connection is detected
• RTC alarm is detected
• -> This mode is not used within TF4
Reset
When the UEM enters RESET mode from PWR_OFF mode the watchdog is enabled. If the
VBAT fails to rise above the power-up voltage level V
elapses, the UEM will enter PWR_OFF mode. Otherwise after a 200 ms delay the regula-
tor VFLASH1 will be enabled and after a additional delay of 500 µs the regulators VANA,
VIO, VCORE and VR3 will be enabled. All other regulators i.e. VFLASH2, VSIM, VR1, VR2
and VR4 – VR7 are software controlled and disabled by default. After an additional delay
of 20 ms the UEM enters PWR_ON mode.
Power on
In PWR_ON the UEM is fully functional in the sense that all internal circuits are powered
up or can be by means of software. The UEM will enter PWR_OFF mode if VBAT drops
for a period of time longer than 5 µs. The UEM will furthermore enter
below V
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PWR_OFF mode if either of the watchdogs Operational State Machine (approx. 100 µs),
Security (32 sec.) or Power Key (4 sec.) elapses or if any of the regulators triggers the
thermal protection circuitry
Sleep
The UEM can be forced into SLEEP mode by the UPP by setting the input SLEEPX low for
more than 60 µs. This state is entered when the external UPP activity is low (phone in
sleep) and thereby lowering the internal current consumption of the UEM. The regulator
VANA is disabled and VR1 – VR7 are either disabled or in low quiescent mode.
From SLEEP the UEM enters PWR_ON if SLEEPX goes high, PWR_OFF mode if watchdog
elapses or BACK_UP mode if VBAT drops below V
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and VBACK > V_BU
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Copyright © 2005 Nokia Corporation.
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). The regulator VRTC that supplies the real time
(3.1 V) before the watchdog
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.
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Nokia Customer Care
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Issue 2.0 Mar/2005
.