General Configurations
6
SLVUBA5 – October 2017
Copyright © 2017, Texas Instruments Incorporated
TPS26624-25 Evaluation Module
ADVANCE INFORMATION
4.4
Test Procedure
4.4.1
Current Limit Test
Use the following instructions to verify the current limit and the latch feature.
1.
shows how to setup the oscilloscope for CH1.
Table 5. TPS26624-25EVM Oscilloscope Setting for Current Limit Test
Oscilloscope Setting
CH1 Probe Points
CH2 Probe Points
Channel 1 = 20 V/div
VIN1 (TP3)
VIN2 (TP10)
Channel 2 = 20 V/div
VOUT1 (TP4)
VOUT2 (TP11)
Channel 3 = 50 V/div
FLTb1 (TP1)
FLTb2 (TP8)
Channel 4 = 500 mA/div
Input current into T1 + wire
Input current into T3 + wire
Trigger source = Channel 4
Trigger level = 500 mA ±100 mA
Trigger polarity = Positive
Trigger mode = Single sequence
Time base
800 ms/div
800 ms/div
NOTE:
If an electronic load is used, ensure that the output load is set to constant resistance mode
and not constant current mode.
NOTE:
Measuring
Current Limit
values on the oscilloscope can easily cause 8% error from
anticipated values listed in
.
2. The jumper setting for the different current limit test is shown in
.
3. Set the current limit to 880 mA by installing the J4 and J8 jumper in position 1-2.
Table 6. TPS26624-25EVM Jumper Setting for Current
Limits
CH1, CH2 Jumper Position
(J4, J8)
Load Current Limit
1-2
880 mA
3-4
500 mA
5-6
250 mA
7-8
150 mA
9-10
25 mA
4. Set the power supply on CH1 to 24 V and the output load on CH2 to 120 ±1
Ω
and enable the power
supply and load on CH1.
5. Set the trigger on the oscilloscope and change the load to 24 ±1
Ω
.
6. Verify that input current is limited as per the setting in
and the device is in latched mode as
shown in
7. The level of the current pulse should match with the load current limit setting in
8. After the oscilloscope triggers, turn off the load.
9. Connect the oscilloscope to CH2 and verify the same behavior on CH2 by repeating the procedure.
