User Guide

PAMS
Technical Documentation
NSE–8/9
System Module
Page 2– 48
Issue 1 07/99
Charging
At the 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.
V–charge_in
PSCC
GND
CCONT
Charge_Ctrl
Charge_GND
CHARGER
PWM_OUT
TRANSCEIVER
R137
Vchar_adc
BSI_adc
R100
R117
30V
VCH
VBat
Vchout
GND
NOT IN ACP–7 or –8
CCONTINT
PWM
RSSI_adc
1.5A
MAD2PR1
MAD2PR1
Ctim
MAD2PR1
Charge_off
PSCC_PWM
R140
Vbb
R142
R101
C158
N100
V105
V114bV114a
C126
C122
Vb
Figure 13. Charging Block Diagram
The PSCC is the charging control ASIC, basically a CHAPS known from
DCT3 but modified for operation on lower supply level and reduced for 2
cell NiMH battery only. The ASIC has the following main functions:
– controlled low drop power switch
– input transient voltage protection
– thermal self protection
– output over voltage protection (voltage limit for phone hardware)
– start–up regulator with limited charge current, Istart
– provision for soft switching (external capacitor needed), C126
– control of different charger types (different PWM frequencies 1Hz and 32Hz)