Charging - Nokia RH-9 Series Ccs Technical Documentation

RH-9
System Module & UI
tionality can be found in next section.

Charging

RH-9 supports the NMP Janette Charger interface.
Charging is controlled by the UEM ASIC, and external components are mounted for EMC,
reverse polarity and transient protection of the input to the baseband module. The
charger connection is through the system connector interface. Both 2- and 3-wire type
chargers are supported.
The operation of the charging circuit has been specified in such a way as to limit the
power dissipation across the charge switch and to ensure safe operation in all modes.
V C H A R
P W M
Charger Detection
Connecting a charger creates voltage on VCHAR input of the UEM. When VCHAR input
voltage level is detected to rise above VCH
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.
3. Check that the charger is within the charger window.
If the charger is accepted and identified, the appropriate charging algorithm is initiated.
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Figure 2: UEM charging circuitry
U E M
V C H A R in
O ve r
T em p .
D e te c tio n
S w itc h
D rive r
C trl
L o g ic
W atch D o g
P W M
G en e rato r
ãNokia Corporation
CCS Technical Documentation
V C H A R o u t
V m str
C u rre n t
S e n sin g /
V B A T T
L im it
+
C o m p
V B A T T lim
-
threshold by UEM charging starts.
DET+
V B A T T
Issue 1 11/02