Battery Charging; Startup Charging - Nokia NSE–3 SERIES Service Manual

NSE–3
System Module

Battery charging

The electrical specifications give the idle voltages produced by the ac-
ceptable chargers at the DC connector input. The absolute maximum in-
put voltage is 30V due to the transient 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 execution 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 charg-
ing, the startup current is switched off. 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 3 – 18
LIM
TRANSCEIVER
VOUT
CHAPS
RSENSE VCH
1u
GND
PWM
100k
22k
1n
10k
Symbol
Vstart
Vstarthys
Istart
Technical Documentation
2A
VIN
30V
CHRG_CTRL
L_GND
Min Typ Max
3.45 3.55 3.75
80 100 200
130 165 200
Original 11/97
PAMS
CHARGER
NOT IN
ACP–7
Unit
V
mV
mA