Hi Takahiro Nishizawa,
The time from Overcurrent event to shutdown depends on amount of overload beyond the set current limit.
Here is the explanation for TPS259241 device and same holds true for the devices you asked.
In current limit mode, the device maintains constant current value which was set at Rilim. The power dissipation across the device is (VIN-VOUT)*I_limit. As VOUT value depends on amount of overload, the power dissipation and hence the duration the device operates before thermal shutdown depends on amount of overload.
For example Vin=5V and current limit value is 2A. When the output is loaded with 1ohm, it is an overload event and output voltage VOUT becomes 2A*1ohm=2V. The power dissipation across the device is (5-2)*2=6W. The device operates for 400ms at 25deg before thermal shutdown.
For example Vin=12V and current limit value is 3.5A. when output is shorted VOUT=0, the power dissipation is (12V-0)*3.5A = 42W. The device should operate for 2ms at 25deg before thermal shutdown.
Regards,
Rakesh
