User Guide

CCS Technical Documentation 2 - System Module
RH-26
Issue 1 02/04 ©Nokia Corporation Page 21
Figure 5: UEMK charging circuitry
Charger detection
When connected, a charger creates voltage on VCHAR input of the UEMK. When VCHAR
input voltage level is detected to have risen above VCH
DET+
threshold by CHACON, the
charging process starts. VCHARDET signal is generated to indicate the presence of the
charger. The charger identification is controlled by EM SW.
The charger recognition is initiated when the EM SW receives a ”charger connected”
interrupt. The algorithm consists of the following three steps:
1 Check that the charger output (voltage and current) is within safety limits.