User Guide

NHB–3
Technical Documentation
PAMS
Cigarette Lighter Charger LCH–2
Original 26/97 Page 4
Cigarette Lighter Charger LCH–2
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General
The LCH–2 cigarette lighter charger is used for charging the battery of the
handportable phone from the 12 or 24 V cigarette lighter socket of a motor ve-
hicle. The charger is provided with LED charging indication.
Technical Summary
States of Charge and Charge Control
The LCH–2 cigarette lighter charger is used for charging a handportable phone
from a car battery. A constant–current or constant–voltage output is provided
depending on the operating state of the phone.
Charge current is supplied through a series switch transistor located in the
phone. When the transistor is on the charger supplies a constant current to the
phone. The phone is then in the rapid charge mode.
When the transistor is off no current is supplied to the phone and the charger is
in the constant–voltage mode.
Once fully charged in the rapid charge mode, the battery is kept full by means
of pulsed charging. Current is switched on and off at a variable duty cycle and a
frequency of a few Hz.
Charge Indication
Charger states are indicated with a dual–colour LED located in the cigarette
lighter charger unit.
In addition, the phone LCD contains a three–bar battery status display, opera-
tive when power for the phone is on.
”Charging sequence active” (state A) is indicated by the bars being lit sequen-
tially, starting from the bottom one.
”Battery full” (state B) is indicated by all three bars steadily lit.