Follow the instructions to verify the current limit and various fault response modes like auto-retry, latch and circuit breaker with auto-retry:

1. Set up the oscilloscope as listed in Table 4-8.
   Table 4-8 TPS2640EVM Oscilloscope Setting for the Current Limit Test

   Oscilloscope Setting	CH1 Probe Points	CH2 Probe Points
   Channel 1 = 10V / div	VOUT1 (TP3)	VOUT2 (TP12)
   Channel 2 = 10V / div	VIN1 (TP2)	VIN2 (TP11)
   Channel 4 = 2 A / div	Input current into T1 +Ve wire	Input current into T3 +Ve wire
   Trigger source = Channel 2
   Trigger level = 12 V ±1V
   Trigger polarity = Rising
   Trigger mode = Single
   Time base	100 ms / div

   Note:

   Measuring the current limit value on the oscilloscope can easily cause ±10% error from the typical expected values as listed in Table 4-9.

    

2. Set the current limit to 2.23 A by installing the J5/J12 jumper in position 1-2.
3. The jumper setting for different current limits is shown in Table 4-9.
4. Set the current limit response to auto-retry by installing the J4/J11 jumper in position 2-3.
   Table 4-9 TPS2640EVM Jumper Setting for Current Limits

   CH1, CH2 Jumper Positions (J5, J12)	Load Current Limit (A)
   1-2	2.23
   3-4	1.5
   5-6	1
   7-8	0.2

5. Set the load resistance to 6 Ω ±1 Ω and the power supply voltage to 24 V.
6. Enable the load.
7. Enable the power supply and verify the current limit magnitude and auto-retry fault response waveform as shown in Figure 4-3.
   Figure 4-3 J5/J12 = 2-3 Position, Current Limit (2.23 A), Auto-Retry Mode
8. Disable the power supply.
9. Set the current limit response mode to latch-off by installing the J4/J11 jumper in the position 1-2.
10. Set the load resistance to 6 Ω ±1 Ω and enable the load.
11. Enable the power supply and verify the current limit magnitude the latch-off fault response waveform as shown in the Figure 4-4.
    Figure 4-4 J5/J12 = 1-2 Position, Current Limit (2.23 A), Latch-Off Mode
12. Once the device is latched-off, either the power supply or the SHDNb should be recycled to re-enable it.
13. Change the load resistance to 16 Ω ±1 Ω.
14. Press and release the reset switch (S1/S2) to re-enable the device from latch-off mode and verify the recovery or restart waveform as shown in Figure 4-5.
    Figure 4-5 Restart From Latch-Off Mode
15. Disable the power supply.
16. Set the current limit response mode to circuit breaker with auto-retry by uninstalling the J4/J11 jumper.
17. Set the load resistance to 6 Ω ±1 Ω and enable the load.
18. Enable the power supply and verify the circuit breaker with auto retry fault response waveform as shown in Figure 4-6.
    Figure 4-6 J5/J12 = Floating, Current Limit (2.23 A), Circuit Breaker With Auto-Retry Mode