CCS Technical Documentation
Troubleshooting - Baseband
RH-34
Issue 1 11/2003 Confidential
©
2003
Nokia Corporation
Page 19
Figure 6: Charging circuitry
Charger Detection
Connecting a charger creates voltage on VCHAR input of the UEM. When VCHAR input
voltage level is detected to rise above 2 V ( threshold) by UEM charging starts.
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.
R200
V100
battery