User Guide

CC Technical Documentation Troubleshooting - Baseband
RM-11
Issue 1 02/2004 ©2004 Nokia Corporation Confidential Page 21
Figure 15: Charging circuitry
Charger Detection
Connecting a charger creates voltage on the VCHAR input of the UEM. Charging starts
when the UEM detects that the VCHAR input voltage level is above 2 V
(VCHdet+ threshold). The VCHARDET signal is generated to indicate the presence of the
charger for the SW. The charger identification/acceptance is controlled by EM SW.
The charger recognition is initiated when the EM SW receives a "charger connected"
interrupt. The algorithm basically consists of the following three steps:
1. Check that the charger output (voltage and current) is within safety limits.
2. Identify the charger as a two-wire or three-wire charger.
3. Check that the charger is within the charger window (voltage and current).
If the charger is accepted and identified, the appropriate charging algorithm is initiated.
Figure 16: Charging circuit
CHARGER(4:0)
________
F100
0
2
1.5A
L1002
X102
1
42R/100MHz
"VCHARIN"
V100
22p
C110C106
1n0