Vin
V_EN/SET
Vout
V_0.1 ohm_BAT
Test Summary
www.ti.com
5. Switch, S1, DOWN, then back UP. The scope captures one pulse on CH2 (
). The pulse must
be less than 1.5-ms wide. If too wide, the potentiometer, R7, can adjust the pulse width.
6. Verify that the input current changes from 0.4 A to 0.51 A (one pulse programmed the IC for ISET
mode). The ISET resistor, 1 k
Ω
, programs the ISET mode to ~0.51 A. Note that the IC can only be
programmed once. If a different program level is desired, the part must be reset by cycling power or
pulling EN/SET high to disable the IC.
7. Remove shunt JMP6, and verify that the input current goes to zero. Removing the shunt, JMP6, allows
EN/SET to be pulled up. This disables the charge and allows programming to be done once EN/SET is
pulled back low by replacing the shunt JMP6.
8. Replace shunt on JMP6, and move shunt on JMP1 to JMP2 (two-pulse programming). The charger
returns to the USB500 mode, delivering ~400 mA. If the IC comes up in a different mode, then while
placing the shunt on JMP6, a contact bounce occurred and the IC was programmed. Remove and
replace the shunt if this happens.
9. Switch, S1, DOWN, then UP to program charger to USB100 mode (
10. This procedure can be repeated (steps 7 to 9) for the shunt on any jumper JMP1 through JMP5 to
program one to five pulses, respectively. Note that programming three pulses puts the IC in PTS mode
and delivers > 2.3 A if the source current is available and the load is great enough. This mode is
intended for production testing without a battery. If a less-than-full battery is connected, the current
may exceed the recommended charge current of the battery or the charger circuit. For maximum
current, the duty cycle must be less than 20% and for no longer than 10 ms. See the data sheet for
programming information (
).
11. Verify that the LDO output voltage on DMM#2 measures ~4.9 Vdc, 0.1 V.
12. Allow battery to charge to full and verify that D2 LED turns off.
13. Discharge battery below 4.1 V, and verify that the charging is enabled and the D2 CHG LED is off for
the second and subsequent charges.
14.
shows the power up and timing of the Stat pins and charge current.
Figure 2. One-Pulse Programming Shows Change From USB500 to ISET Mode
4
1.1-A, Single-Input, Single-Cell, Li-Ion Battery Charger With 50-mA LDO and 2.3-A Production Test Support
SLUU358 – April 2009