Texas Instruments bq24072RGTR User Manual Download Page 5

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Test Summary

EN1/2 modes of operation.

11. SET JMP4 (EN2) to VSS. Verify that the input current is less than 500 mA (USB 500-mA mode). If the

input current is restricted due to USB mode, or if the adapter is current limiting, the OUT pin drops in
voltage and enters the DPM mode, if the system current is less than the restricted input current. This
IC must be in DPM mode with the system voltage at the DPM

12. Set JMP5 (EN1) to VSS and verify USB 100-mA mode. The system load is more than the allowed 100

mA on the input, so the OUT voltage drops to the battery voltage, and the battery FET is switched on
and supplements the input current. Verify that Vout has dropped just below the battery voltage and the
battery is supplying Ibat, ~(Vout/10

Ω

– 100 mA).

13. Set JMP4 (EN2) to HI to return to the ISET mode where the programmed current is ~0.9 A.
14. Set JMP3 to HI, and verify that the charging is disabled and that the CHG LED (D1) turns off. Verify

that the system is still powered by the input. See

Figure 3

15. Set JMP3 to VSS, and verify that charging continues and that D1 turn on.
16. Record the OUT voltage and battery charge current. Adjust R8 CCW until the input current starts to be

reduced (~2 turns). Note how the OUT voltage drops and the charge current is reduced as the input
current limit loops kicks in and limits the input current. Adjust R8 to its original position

17. On the bq24075 IC, set JMP2 HI, and verify that the BAT FET turns off and allows no charging or

discharging of the battery.

18. Adjust the R16 (TS-Pot) up or down until the TS threshold is reached. Verify that the charging current

is disabled. Return the TS resistance within the normal range and verify the continued charging
operation.

19. Allow the battery to continue to charge until the battery reaches voltage regulation, ~4.2 V ±40 mV for

bq24072/3/4/5/9(T) and 4.1 V ±4 mV for bq24079(T). Verify that the voltage is regulated as the current
tapers over the next one-to-two hours depending on the battery capacity. See

Figure 4

for a charge

profile (time in plot is not proportional to actual charge time).

20. Verify that the current tapers to around 90 mA (9 mV on DMM#3) when termination occurs. Note on

the ’72 and ’73 ICs that termination can be disabled by setting the TD pin HI (JMP2). Also note that on
’74, the ITERM resistor (R10) can adjust the termination threshold.

21. Verify that the LED, D1, turns off and the current drops to zero.
22. Turn off P/S#1, and allow the system load to discharge the battery until a refresh charge is initiated.

Verify that the battery voltage dropped to ~4.1 V for bq24072/3/4/5 and to 4.0 V for bq24079(T) prior to
refresh.

23. Verify that the LED, D1, did not turn on for the refresh cycle.

This concludes the procedure for demonstrating the features of this power path charger. See the data
sheet for more detailed explanations and instructive waveforms.

SLVU274C – November 2008 – Revised May 2010

bq24072/3/4/5/9(T) and bq24230/2 1.5-A Single-Chip Li-Ion —and Li-Polymer

Charge Management IC EVM