Test Summary
2.4
Recommended Test Procedure
The following test procedure is useful for evaluating the charger IC outside of a real system, if no battery
is available to connect to the output and a simulated battery is needed.
2.4.1
System Voltage and Output Current (bq24272 only)
1. Ensure that the
steps are followed.
2. Connect the output of PS #1 in series with CM #1 to J2 (IN, GND).
3. Connect voltage meter 1 (VM #1) across J1 or TP1 and J3 (IN, GND).
4. With PS #2 disabled, turn on PS #1.
5. Ensure the electronic load is on current mode and set the current to 1 A or turn down the resistor
decade box until CM #3 measures 1000 ±100 mA.
6. Measure:
Measure on VM #3
→
V(J4(SYS), J8(GND)) = 3.7 ±150 mV.
Observe
→
D1 and D2 are on.
7. Move JP2 (CD) = HI.
8. Measure on VM #3
→
V(J4(SYS), J8(GND)) = 0 V.
9. Disable PS #1 and disconnect electronic load or resistor box and CM #3 from the HPA759 board.
2.4.2
Charge Voltage and Current Regulation of IN
1. Ensure that the
steps are followed.
2. Connect the output of PS #1 in series with current meter (multimeter) #1 (CM #1) to J1 and J3 or J2
(IN, GND).
3. Connect voltage meter 1 (VM #1) across J1 or TP1 and J3 (IN, GND).
4. Move JP2 to HI.
5. Turn on PS #1 and PS #2 if used.
6. Return JP2 to LO.
7. Software setup:
•
Press the READ button to obtain the current settings.
•
Set Write On Change to ON if not already set.
•
Set Reset Watchdog Timer to update every 5 seconds.
•
Uncheck Disable Charging if checked.
•
Check Enable STAT/INT Outputs.
•
Set Battery Regulation Voltage to 4.20 V.
•
Set USB Input Current Limit to 2.5 A.
•
Set Charge Current to 1000 mA.
•
Click the READ button at the top of the window, and confirm that the previous settings remain.
8. Adjust PS #2 so that the voltage measured by VM #2, across BAT and GND, measures 3.2 V ±50 mV.
9. Adjust the power supply so that VM #1 still reads 6 V ±100 mV if necessary then
Measure on CM #2
→
I
CHRG
= 1000 mA ±100 mA
Measure on CM #1
→
I
IN
< 850 mA
Observe
→
D1 and D2 are on.
10. Turn off PS #1 and PS #2.
12
WCSP-Packaged bq24272/273 Evaluation Modules
SLUU916 – April 2012
Copyright © 2012, Texas Instruments Incorporated
