EV2903 Switch and Jumper
Settings
S1
Cell Selection.
S1 selects three-cell (set
to 3) or four-cell (set to 4) configuration.
JP7
Supply Regulation.
Set jumper JP7 to
INT-I to use the on-board, voltage-limited
current source. Set JP7 to EXT-I to select
off-board charging supply.
JP9
EDV.
JP9 selects the end-of-discharge
voltage at which the bq2903 disconnects
the battery stack from the load. To select
1.0V EDV, leave jumper off to let V
SEL
floating.
JP8
Internal or External Discharge FET.
JP8 selects the external FET for discharge
loads greater than 400mA. Set jumper to
EN to enable the external FET, or set it to
DIS to disable the external FET.
EV2903 Connections
J1
DRV.
Auxiliary discharge FET driver out-
put from the bq2903 to connect to gate of a
user-selectable, external FET. Source should
be connected to GND and drain to LOAD-.
DONE.
This TTL-compatible output sig-
nifies a charge completion by going high.
Valid only when DC is applied.
GND. Charging supply ground.
LOAD+.
Connection for the load to the
high side of the battery stack.
LOAD-.
Connection for the load return.
J2
Use this connection when using the on-
board voltage-limited current source. This
connector accepts an unregulated voltage
between 9-15V DC at a minimum of 300mA.
JP7 should also be in the INT-I position. Do
not use J3 in conjunction with J2.
J3
Use this connection when bypassing the
on-board current source and providing an
external charging source.
The external
supply should be a 300mA current source
with a voltage compliance between 8-10V.
JP7 should also be in the EXT-I position.
J2 should not be used in conjunction with
J3.
P1
Serial data bus connection
. This con-
nection is made to the RS-232 cable con-
necting to the serial port of the PC.
EV2903 Configuration
The EV2903 Evaluation Board operates with or without
the Interface Program. Configure the board first before
connecting the batteries and the RS-232 cable
.
Step 1
Configure all switches and jumpers to
their desired settings.
The factory de-
fault settings are:
JP7: INT-I
JP9: EDV = 1V
JP8: External FET
Step 2
If using an off-board discharge load FET,
connect the gate to the DRV output on J1,
connect the source to GND on J1, and
connect the drain to LOAD- on J1.
Step 3
Connect the DC power supply to either J2
or J3, depending on the use of external or
on-board regulation.
Step 4
Connect the RS-232 cable to connector P1
on the EV2903 and to an available serial
port on the PC (optional).
Installing the User Interface
Program
The EV2903 board uses a bq2014 Gas Gauge chip on
board to monitor the state of charge of the batteries and
to provide an easy user interface to this evaluation
board. The user communicates with the bq2014 through
the User Interface Program, which runs on any IBM
PC-compatible computer in the Windows 3.x environ-
ment (a 486-33MHz or better is recommended).
Before running the program, you must first install it
from the floppy disk to the hard drive. To install the
User Interface Program, insert the diskette into the disk
drive and choose Run from the File menu in Program
Manager. Type “A:\setup” (substituting the appropriate
drive letter for “A”) and press Enter. The installation
program will prompt for the destination directory (select
“OK” to accept the default).
Using the EV2903 Program
To run the program, double-click on the EV2903 icon in
the EV2903 program group. All of the status monitors
and functions are controlled from the EV2903 Interface
screen, Figure 1.
2
EV2903
