DSC-F1 (serv.man2) - Sony Digital Camera Service Manual (repair manual). Page 13

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The lithium ion rechargeable battery is automatically charged when the following conditions are satisfied.

• When the HI microprocessor is started
• When the AC adapter is connected (when the UNREG voltage is higher than 5.2V)

(Detected by the C332 voltage of the HV board)

• When the lithium ion rechargeable battery is connected

(Detected by Pin @§ of IC301 of the HV board)

• When the function dial is OFF

(Detected by the MODE SW Pin @º of IC301)

The instruction manual describes that “to charge, switch the function dial to camera or playback once, and then set it back

to OFF again”.

However, if the above conditions are satisfied, the battery will be charged automatically even if the function dial is not

rotated.

Only when the HI microprocessor is reset, it will be necessary to rotate the function dial to start the microprocessor.
(when the unit is not operated for a long period of time, when the reset button is pressed, etc.)

The charging time is approximately 8 hours at the maximum and the charging current is approximately 750 mA. These

values are varied according to the remaining power of the rechargeable battery.

Charging consists of normal charging and trickle charging. If the rechargeable battery voltage has dropped excessively due

to long term storage, first trickle charging is performed, and then normal charging is performed when the voltage recovers to
a certain extent.

The HI microprocessor is incorporated in the charging timer, and normal charging completes after 6 hours. However, if the

rechargeable battery voltage was dropped considerable due to long term storage, trickle charging is performed first for about
one hour. Therefore charging may be performed up to 8 hours in some cases.

The LED will continue being lit for 6 hours by the charging timer even if the rechargeable battery has been fully charged.

In addition, if the shutter button is pressed during charging, the charging timer of the HI microprocessor will be reset. In this
case, the charging lamp may not go off for more than 8 hours.

When the AC plug is connected when the chargeable batteries are loaded, Q317 of the HV board is turned ON by the

voltage of the minus side terminal of the chargeable batteries (LI BATT), the wake up signal will be input to the XWP
terminal (Pin &ª of IC301) of the HI microprocessor.

The charging conditions are checked, and if the batteries can be charged, charging is started.

When the LICHGON signal (Pin !¡ of IC301) of the HI microprocessor becomes H, Q006 and Q005 of the DD board turn

ON, and the UNREG voltage is supplied to the charging circuit. When Pin 2 of the PWM controller (IC001) for charging
becomes L, IC001 is started.

A voltage lower than UNREG by 2.5V is output to Pin 3 of the comparator (IC002) by IC003. (Approximately 3.5V

during charging).

The output of Pin 4 of IC002 which is obtained by comparing this reference voltage and the battery feedback voltage input

to Pin 1 of IC002 is input to Pin 8 of IC001 (Approximately 0.6V during charging).

The PWM signal is output from Pin 5 of the PWM controller (IC001) by the input voltage, switched by Q003, and the

charging current flows to the rechargeable battery.

When there is little power remaining in the rechargeable battery, the R001 voltage rises when excessive current flows. As

a result, Q004 turns ON, and the potential of the minus side of the rechargeable battery is raised to restrict the charging
current. The charging current is approximately 750 mA.