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4.1 Battery Operation
An on-board charger circuit is provided, which allows the battery to charge when a DC power supply is
present at the power jack. The charger circuit automatically turns on when a DC power supply is inserted
into the power jack, independent of the power switch. When the fast-charge conditions are met, the char-
ger circuit begins to fast-charge the battery. Fast-charge is active when the
Charge
LED (blue) is on. If the
battery reaches a temperature greater than 50 °C the charger circuit exits the fast-charge cycle. The fast-
charge cycle typically lasts three to four hours when the battery is completely discharged. The end of the
fast-charge cycle is indicated by the
Charge
LED turning off. Anytime that the
Charge
LED is off and the DC
power supply is connected to the E-O Converter, the charger circuit trickle-charges the battery. Trickle-
charge mode helps to maintain a full charge on the battery without over-charging it.
Inserting a DC power supply into an E-O Converter with a full charge on its battery results in a short fast-
charge cycle. A temperature monitor ensures that the charger circuit does not enter fast-charge until the
battery temperature is less than 40 °C. The
Charge
LED will flash to indicate that the battery cannot enter
fast-charge mode. The
Charge
LED stops flashing once the battery temperature falls below 40 °C.
If the battery is severely depleted of charge and the DC power supply is plugged into the E-O Converter, a
pre-charge will occur to condition the battery for a fast-charge cycle. This pre-charge condition is also sig-
nified by the
Charge
LED flashing. Once the battery reaches a minimum voltage, the charger will commence
with the fast-charge cycle.
The E-O Converter uses a nickel-metal hydride rechargeable battery, therefore it is not
necessary to fully discharge the battery before it can be recharged.
When the power switch is in the
ON
position and the DC power supply is connected to the power jack, the
DC power supply powers the board supplies (3.3 V and 2.5 V) for the functional circuitry (data conversion).
Operation of the E-O Converter while the battery is charging can be a useful feature during compliance
testing. The E-O Converter outside of the test environment can be powered by a DC power supply, which
ensures that its battery maintains a full charge. When the battery of the E-O Converter inside of the test
environment is low, indicated by the
Power
LED (yellow) on, the inside and outside E-O Converters can be
switched to allow the empty battery to charge while testing continues. Switching the E-O Converters in this
manner results in minimal down time, and can easily be done between tests.
Once the DC power supply is disconnected, the charger circuit shuts down. If the power switch is
ON
when
this occurs, the board power supplies will continue to be powered by the battery. A full battery charge typi-
cally provides 10 hours of power for MOST50 E-O Converter operation. After approximately eight hours,
the low battery indicator
Power
LED (yellow) turns on. This indicates that there are less than two hours of
battery life remaining and that the battery should be recharged.
To conserve battery charge, the power switch should be turned
OFF
whenever tests are not
being conducted.
