Battery Charging; Startup Charging - Nokia NSB-7 Series Service Manual

NSB-7
System Module

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.
MAD
0R22
VBAT ICHAR
PWM_OUT
MAD
CCONTINT
VCHAR
CCONT
GND

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
VOUT Start-up mode cutoff limit
VOUT Start-up mode hysteresis
NOTE: Cout=4.7 uF
Start-up regulator output current
VOUT=0V....Vstart
Page 14
LIM
VOUT TRANSCEIVER
CHAPS
RSENSE VCH
1u
GND
PWM
100k
22k
1n
10k
Figure 3: Charging Block Diagram
Symbol Min
Vstart 3.45
Vstarthys 80
Istart 130
ãNokia Mobile Phones Ltd.
PAMS Technical Documentation
2A
VIN
30V
L_GND
Typ Max
3.55 3.75
100 200
165 200
CHARGER
Unit
V
mV
mA
Issue 1 06/00