Epson PX-8 - Page 37

REV.-A
2.2.2.2 Main Battery Charging
In the following text, the functions of jumper J2 are summarized. Then, the actual main battery
charging operations are described based in Fig. 2-S.
(1)
J2 jumper
The J2 jumper provides the following functions:
When closed: Disables the charging control; the battery is always charged as long as the AC
adaptor is connected.
When open: Enables the charging control; the battery is charged as follows when the AC
adaptor is connected, depending on
whether power is on or off:
When power is on: The normal charge continues for the first 11 hours, and
then
the trickle charge is used.
When power is off: The normal charge continues for the first eight hours, and
then
the trickle charge is used.
* With jumper 2 open and power off, the circuit remains in the trickle charge
mode, after
the normal charge, for the first eight hours. However, the circuit
automatically returns
to the normal charge mode whenever the battery vol-
tage falls
below 5V.
(2) Charging Operations
• Fig. 2-S is a
timing diagram which illustrates the main battery charging operation when the
charge control is in effect.
POWER switch setting
~------------~/~'------------~ ~-------
W 4.0H U
AC adaptor connection
11.0H
Charge mode
~I
, 11.0H
!E
,
~I
Fully Normal charge Normal charge
charged - - - - - - - - - - - - - - - - - - - - - - - - - -
Battery
voltage
variation
5.0 v
Trickle charge
IE ~:
, '------
Normal charge
...... -+- .......
Normal charge
~ @
voltage-- 1oE""':"----~CD=__ ___ .!OjoIE-E __ ~CV=___ _ ___*)(....;®=----:)*"( ---=@=__~J~)(;__-®c::..6 __
Fig. 2-8 Main Battery Charging Operation
Note: Battery voltages and charging currents:
Voltages:
When fully charged: Approx.5.4V
Low voltage:
Charging currents:
Main battery
Normal charge:
Trickle charge:
Auxiliary battery
Normal charge:
Trickle charge:
Approx. 4.5
to 4.SV
150 to 200 rnA
40 rnA
10mA
1 rnA
2-13