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IC404/pin 100 Output Voltage (CN002/pin 3)
Power
Camera OFF
Camera ON
AC only
0Vdc
0Vdc
Battery Only
0Vdc
3.2Vdc
AC + Battery
3.2Vdc (charging amber light is
on)
0Vdc
AC + Battery
(fully charged
battery)
Square wave 1 sec On / 1 sec Off
duty cycle (charged battery
amber light is off) *
0Vdc
Battery Compartment Switch
The switch in the battery compartment, J901, remains grounded with or
without a battery inserted. This switch only opens when the car battery
cord or battery down adjustment test cord is inserted.
The switch permits the camera to operate with a special non-Info-Lithium
power source. As a precaution, battery charging is inhibited when this
switch is open.
Defective Switch Symptoms
If the switch is open (defective) there will be no battery life information on
the camera’s display and the battery cannot be charged because IC404
does not expect an Info-Lithium battery to be present.
Charge the battery (with AC adapter)
This Battery Power circuit permits the battery to power the camera when
the camera is turned ON. However when the camera is turned OFF, this
Battery Power circuit works in exactly the same way to charge the battery.
The Battery Charging operation occurs under the following conditions:
1. The AC adapter must be connected.
2. A battery must be connected.
3. The camera must be OFF.
4. The Battery Charge Determination Circuit must determine if the bat-
tery needs charging after a test charge.
5. This Battery Power Circuit turns ON to charge the battery.
6. The battery’s microprocessor informs IC404 to stop the charge when
the battery is charged.
Test Charging the Fully Charged Battery
After the battery is charged, the rear panel amber charge light goes out.
This circuit changes to test charge the battery while the camera is still
OFF. IC404 changes from outputting a HIGH at pin 100 for battery charg-
ing to a one-second square wave to test charge the battery. This momen-
tarily connects the DC In voltage to the battery at a one-second rate,
keeping the battery charged. During this time the battery’s micro can also
determine if battery charging is necessary and informs IC404 if the bat-
tery should switch back to the charging mode.
A dynamic battery test method can be performed by either placing a load
on the battery (measure the current flowing out) or by test charging the
battery (measure the current flowing in). This dynamic test method is
better than just measuring the battery terminal voltage to determine if
charging is needed.
