Battery Charge Determination - Sony Mavica MVC-FD85 Training Manual

Battery Charge Determination

This circuit test charges the battery to determine if charging is needed.
Test charge pulses are produced when the AC adapter is plugged in and
the camera is off. The test charge pulses stop when a battery is inserted
to complete the test.
The Battery Charging operation begins when the first three conditions are
met:
1. The AC adapter plug is connected and supplying DC In voltage.
2. The battery is inserted.
3. The Camera is OFF.
4. This Battery Charge Determination circuit test charges the battery.
5. This Battery Charge Determination circuit disconnects.
6. The amber Battery Charge light turns ON (not shown.)
7. Battery Charging comes from Q001.
8. Battery Charging ends.
9. Battery Charge Inhibit
The AC adapter plug is connected and supplying DC In voltage
When the AC Adapter plug is inserted, J902/pin 3 is grounded at the jack
by the plug. This ground is applied to HI Control IC404 to inhibit the
battery from operating the camera as long as the DC In plug is connected.
Voltage from the AC adapter passes through F005 and is detected by AC
sense input of IC404/pin 72. This causes IC404 to output pulses at one-
second intervals from pin 27 (CN002/pin 4). These pulses will be used in
step 4 to test charge the battery.
The Battery is inserted
After the battery is inserted, IC404/pin 71 (via F004) senses its voltage.
The switch in the camera's J901 compartment is normally closed (J901/
pin 3 = ground) for IC404 to expect data from an Info-Lithium battery. The
data is used to turn on and shut off the charge circuits.
25
The Camera is OFF
Battery charging only works when both power sources are connected and
IC404 has determined that the camera is off.
This Battery Charge Determination circuit test charges the bat-
tery
IC404/pin 27 (CN002/pin 4) will output a one-second square wave until
the battery's charge condition is determined. This square wave momen-
tarily charges the battery so the battery's microprocessor can determine if
a charge is needed. If a charge is needed, the battery's microprocessor
informs IC404 and IC404 starts the charging.
The square wave from IC404/pin 27 is applied to Q003 to simulate the
battery charging. When Q003 turns ON, so does Q002. Q002 is con-
nected between the DC In jack and the battery jack so when Q002 con-
ducts, current flows through D002 into the battery during these one-sec-
ond test charges.
During one or two of these one-second test charges, the battery's micro
can determine if charging is needed and relay that information as data
from J901/pin 2 to IC404/pin 48. This occurs right after the battery is
inserted or the camera is turned off.
This Battery Charge Determination Circuit disconnects
In the previous test charge, when the battery was inserted or the camera
was turned off, IC404 determined if the battery needed charging or not.
IC404 will take one of two courses of action:
No charge needed – Continue to test charge the battery at one-second
intervals with pulses from IC404/pin 100 using the battery power circuit.
Charging needed – Charge by outputting a steady high from IC404/pin
100 using the battery power circuit.
In either case, the one-second pulses from this battery determination cir-
cuit will no longer output IC404/pin 27.