Charger Detection - Nokia 1265 Description And Troubleshooting

1265 (RH-103)
Baseband Description and Troubleshooting

Charger Detection

Connecting a charger creates a voltage on the VCHG ("VEXT_DC" pin in 1265
schematic) input of the PM. Charging starts when the PM detects the VCHG input
voltage level above 3.3V (Min. working voltage of VCHG pin).
The VCHG signal of PM is generated to indicate the presence of the charger for the
software. The power management (PM) software controls the charger identification/
acceptance. The charger recognition is initiated when the EM software receives
a "charger connected" interrupt. The algorithm basically consists of the following
three steps:
1. Check that the system current (the collector current of PNP transistor) is within
safety limits.
2. Check the power consumption of PNP transistor is within safety limits.
3. Check that the charger is within the charger window (voltage and current). If the
charger is accepted and identified, the appropriate charging algorithm will be
initiated.
Page 16 © 2007 Nokia Corporation
Figure 13: Mobile terminal DC Jack Circuit.
Figure 14: PNP Charging Control Circuit.
Company Confidential Issue 1 04/2007