Test Summary
•
Set
Battery Regulation Voltage
to 4.20 V.
•
Set
Input Current Limit
to 2.5 A.
•
Set
Charge Current
to 2000 mA.
•
Click the
READ
button at the top of the window and confirm that the previous settings remain.
12. To test charge current regulation, adjust the PS #1 power supply so that VM #1 still reads 5 V and
PS#2 so that the voltage measured by VM#2 is 3.6 V.
Measure on CM#2
→
I
CHRG
= 2000 mA ±100 mA
Measure on CM#1
→
I
IN
< 1600 mA.
13. To test input current limit, lower the software's
Input Current Limit
setting to 900 mA then readjust PS
#1 so that VM #1 reads 5 V and PS#2 reads 3.6 V.
Measure on CM#2
→
I
CHRG
< 2000 mA.
Measure on CM#1
→
I
IN
= 800 mA – 900 mA .
14. To test minimum system voltage and DPPM, return the software's
Input Current Limit
setting to 2500
mA then lower PS #2 until VM#2 reads 3.3 V. Add an external resistive or constant current load across
J13 and J5 that does not draw more than 2.5 A from SYS.
Measure on VM#3
→
3.44 V – 3.55 V.
Measure on CM#2
→
I
CHRG
= 2000 mA ±100 mA minus the load current on SYS.
15. To test V
INDPM
function, remove the load on SYS, adjust PS#1 so that VM#1 reads 5 V, adjust PS# 2
so that VM#2 reads 3.6 V and then lower the current limit setting on PS#1 to below the software's
Charge Current
setting.
Measure on VM#1
→
V
IN
= software's V
INDPM
level (default of 4.2 V).
Measure on CM#2
→
I
CHRG
< 2000 mA.
16. To test battery regulation and charge termination, return the PS#1 current limit to 4-A and confirm that
the software's
Enable Termination
box is checked then slowly increase PS#2 until VM#2 reaches 4.2
V.
Measure on CM#2
→
I
CHRG
slowly tapers to the software's I
TERM
setting (default of 150 mA) and then
drops to zero.
Observe
→
LEDs turn off.
17. To test battery supplement mode, lower PS #2 until VM#2 reads 3.6 V. Add an external resistive or
constant current load across J13 and J5 that draws more than 2 A from SYS.
Measure on VM#4
→
3.6 V - I
BATSUP
× R
DSON(BATFET)
.
Measure on #2
→
I
CHRG
= - I
BATSUP
18. Turn off PS #1 and PS #2.
2.4.2
Helpful Hints
1. The leads/cables to the various power supplies have resistance. The current meters also have series
resistance. Therefore, you must use voltmeters to measure the voltage as close to the IC pins as
possible instead of relying on the supplies digital readouts.
2. When using a sourcemeter that can source and sink current as your battery simulator, it is highly
recommended to add a large (1000 µF+) capacitor at the EVM BAT and GND connectors in order to
prevent oscillations at the BAT pin due to mismatched impedances of the charger output and
sourcemeter input within their respective regulation loop bandwidths. Configuring the sourcemeter for
4-wire sensing eliminates the need for a separate voltmeter to measure the voltage at the BAT pin.
When using 4-wire sensing, always ensure that the sensing leads are connected first in order to
prevent accidental overvoltage by the power leads.
3. For precise measurements of charge current and battery regulation near termination, the current meter
in series with the battery or battery simulator must be removed. An alternate method for measuring
charge current is to either use an oscilloscope with hall effect current probe or place a 1% or better,
thermally capable (for example, 0.010
Ω
in 1206 or larger footprint) resistor in series between the BAT
pin and battery and measure the voltage across that resistor.
11
SLUUBB5A – April 2015 – Revised October 2015
User's Guide for WCSP-Packaged bq24261M 3-A Battery Charger
Evaluation Module
Copyright © 2015, Texas Instruments Incorporated