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NSB-7
System Module
PAMS Technical Documentation
Page 14
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Nokia Mobile Phones Ltd.
Issue 1 06/00
Battery charging
The electrical specifications give the idle voltages produced by the acceptable chargers
at the DC connector input. The absolute maximum input voltage is 30V due to the tran-
sient suppressor that is protecting the charger input. At phone end there is no difference
between a plug-in charger or a desktop charger. The DC-jack pins and bottom connector
charging pads are connected together inside the phone.
Figure 3: Charging Block Diagram
Startup Charging
When a charger is connected, the CHAPS is supplying a startup current minimum of
130mA to the phone. The startup current provides initial charging to a phone with an
empty battery. Startup circuit charges the battery until the battery voltage level is
reaches 3.0V (+/- 0.1V) and the CCONT releases the PURX reset signal and program exe-
cution starts. Charging mode is changed from startup charging to PWM charging that is
controlled by the MCU software. If the battery voltage reaches 3.55V (3.75V maximum)
before the program has taken control over the charging, the startup current is switched
off. For accessory detection, startup current is possible cut via CCUT line. The startup
current is switched on again when the battery voltage is sunken 100mV (nominal).
Parameter
Symbol
Min
Typ
Max
Unit
VOUT Start-up mode cutoff limit
Vstart
3.45
3.55
3.75
V
VOUT Start-up mode hysteresis
NOTE: Cout=4.7 uF
Vstarthys
80
100
200
mV
Start-up regulator output current
VOUT=0V....Vstart
Istart
130
165
200
mA
VIN
CHAPS
10k
1n
PWM
VBAT
GND
CCONT
L_GND
CHARGER
PWM_OUT
TRANSCEIVER
0R22
VCHAR
ICHAR
100k
22k
1u
2A
30V
VCH
VOUT
RSENSE
GND
CCONTINT
MAD
LIM
MAD