Nokia RH-9 Series Ccs Technical Documentation page 28

RH-9
System Module & UI
(1)
Input voltage range
Input capacitance
Signal Min
VBATADC 2.7
ICHAR VBATADC
VCHARADC 0.1
BSI 0
BTEMP 0
PATEMP 0
VCXOTEMP 0
HEADINT 0
HOOKINT 0
LS 0
KEYB1 0
KEYB2 0
AD converter is calibrated in production.
Battery Voltage Measurement A/D Channel (
The battery voltage is scaled inside the UEM in order to avoid external components. The
maximum battery voltage that gives a full A/D reading is 5.25V.
Battery voltage can be connected to sample and hold circuit either through a resistive
voltage divider or through a voltage scaling circuit. The voltage scaling circuit is used to
get larger input voltage range for the converter than what is achieved with the resistive
divider. The sample and hold circuit is used to measure the battery voltage during trans-
mit burst. Otherwise the S/H circuit is bypassed. Note that both the battery voltage
(VBATADC) and the charger voltage (VCHARADC) are sampled whenever the sampling
function is used.
Charger Voltage Measurement A/D Channel (
This channel is used to measure the charger input voltage VCHAR. The charger input idle
voltage is measured to identify the charger. Associated with the charger voltage mea-
surement an envelope detector is used to detect a rectifier bridge type of charger. Con-
nection of the charger is performed by the rising edge of the charger input. The charger
must be a full wave rectifier. A half wave rectifier charger have to be rejected.
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Table 25: Slow A/D converter input ranges
Typ Max
- 5.25
- VBATADC+0.316
- 1.35
- 2.7
- 2.7
- 2.7
- 2.7
- 2.7
- 2.7
- 2.7
- 2.7
- 2.7
ãNokia Corporation
CCS Technical Documentation
2.7 V
6 pF
Unit Note
V Physical input on UEM is
VBATREGS
V
V
V
V
V Used for CTI
V Not used in NHM-8
V
V
V Not used in NHM-8
V Not used in NHM-8
V Not used in NHM-8
VBATADC)
VCHARADC)
Issue 1 11/02