Charger Detection - Nokia RH-66 Troubleshooting Manual

2115i/2116/2116i (RH-66)
Baseband Description and Troubleshooting
VCHAR
VCHAR in
Over temperature
detection
Watchdog
PWM generator
PWM

Charger Detection

Connecting a charger creates voltage on the VCHAR input of the UEMC. Charging starts
when the UEMC detects the VCHAR input voltage level above 2 V (VCHdet+ threshold).
The VCHARDET signal is generated to indicate the presence of the charger for the
software. The energy management (EM) 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 charger output (voltage and current) is within safety limits.
2. Identify the charger as a 2- or 3-wire charger.
3. Check that the charger is within the charger window (voltage and current).
Page 20
UEMC
Switch driver
Control logic
Figure 11: Charging circuitry
©2005 Nokia Corporation
VCHAR out
Vmstr
Current VBATT
sensing/limit
+
Comp
-
VBATT lim
Company Confidential
VBATT
Battery
Issue 1 03/2005