Charger Detection - Nokia RH-27 Series Technical Documentation Manual

CCS Technical Documentation
V100

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 (VCHdet+ 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.
Issue 1 11/2003 Confidential
Figure 6: Charging circuitry
©2003 Nokia Corporation
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