SLUU200 − July 2004
6
Using the bq241xx (bqSWITCHER
E
)
Table 2. I/O and Jumper Connections (Factory Jumper Selections are shown in BOLD):
ASSEMBLY
−001
−002
−003
−004
−005
U1
Device
bq24100
bq24105(1)
bq24113(2)
bq24115(1)
bq24103(2)
J1
DC+/DC−:Input voltage range (V)
5 to 16
VREG+0.8 to 16(1)
5 to 16
VREG+0.8 to 16(1)
5 to 16(2)
J2
BAT+/BAT−No. cell in series
1
1
1
1
1
J2
Output regulation voltage (V)
4.2
4.2(1)
4.2(2)
4.2(1)
4.2(2)
J5
PG
LED or EXT
LED or EXT
LED or EXT
LED or EXT
LED or EXT
J6
STAT1
LED or EXT
LED or EXT
LED or EXT
LED or EXT
LED or EXT
J7
STAT2
LED or EXT
LED or EXT
N/C no jumper
N/C no jumper
LED or EXT
J8
TTC or CMOD
TTC no jumper
TTC no jumper
CMOD jumper HI
CMOD jumper HI
TTC no jumper
J9
CE
CE jumper LO
CE jumper LO
CE jumper LO
CE jumper LO
CE jumper LO
J10
Cells or FB
No jumper
No jumper
Cells jumper LO
No jumper
Cells jumper low
(1) R5 and R7 can be changed to regulate output between approximately 3.2 V to 15.5 V. Adjust the input voltage as required. Output set to operate
at 4.2 VDC from the factory.
(2) To operate as a two cell version (8.4V), replace battery with a two-series cell pack, set J10 to High and adjust the Input voltage between
9.2 V to 16 V.
2.3
Test Procedure
Setup the evaluation board as described above, by making the necessary I/O connections and jumper
selections. Prior to test and evaluation, it is important to verify that the EVM selected is setup correctly
for the battery pack to be charged (several evaluation modules have a CELLs option that can be
programmed for two different size − number of series cells). It is highly recommended that the battery
pack to be charged has internal proteciton as a safety backup.
1.
Turn on the power supply, preset to the suggested value in Table 2, and approximately 1.7 A for the current
limit setting.
2.
The PG LED should turn on along with STAT1, if the battery is charging.
3.
The bq241xx enters pre-conditioning mode if the battery is below the V
(LOWV)
threshold. In this mode, the
bq241xx pre−charges the battery with a low current programmed by the ISET2 pin. If the R
SET1
and R
SET2
resistors are the same value then the precharge is one tenth the fast charge current (I
PRE−CHG
= 1.33 A/10
= 133 mA) until the battery voltage reaches the V
(LOWV)
threshold or until the precharge timer expires. If
the timer expires then the charge current is terminated and the bq241xx enters fault mode. STAT1 and
STAT2 (if available) LEDs turns off when in fault mode. Note that there are several non-charging modes that
share this status state. Toggling input power or battery replacement resets fault mode.
4.
Once the battery voltage is above the V
(LOWV)
threshold, the battery enters fast charge mode. This EVM
is programmed for approximately 1.3 A of fast charging current. The PG and STAT1 LEDs should be on.
5.
Once the battery reaches voltage regulation (4.2 V) the current tapers down as the battery reaches its full
capacity. The PG and STAT1 LEDs should be on.
6.
When the current reaches the taper termination threshold, set by the R
SET2
resistor, the charge is
terminated. The PG LED should still be on and the STAT1 LED should turn off and STAT2 LED turn on.
7.
If the battery discharges down to the recharge threshold, the charger starts fast charging. The PG LED
should still be on and the STAT2 LED should turn off and STAT1 LED turn on.
An alternative method of testing the EVM is with a source meter, that can sink or source current. This can easily
be adjusted to test each mode, in place of a battery.
3
Schematic
Figure 1 shows the schematic diagram for the EVM.
