Thermal shutdown problem in BTS4140N

[hardwareentw]

Hello Team.

In one of the applications I use the BTS4140N,the output is loaded with 0.5A.

The supply voltage is 45V. the ambient temperature is 70°C.

After some time about 3-5min the limitation of the current starts. The output voltage also drops very sharply.

As soon as this behavior starts. The BTS4140N can no longer be switched off via pin 1 IN. But must be completely de-energized. Is this a normal behavior?

I have a second BTS4140N. This one is connected to the same supply voltage. But it is loaded and controlled separately. If one of the two BTS4140N starts with the behavior, so behaves also the other so. Is this also normal.

Thanks a lot

[Anshika_G]

Hello,

BTS4140N supports thermal shutdown with restart. As soon as your device went to current limit protection , thermal protection feature also starts (more current>more power loss>more heat dissipation> increase in temperature) . Device goes in shutdown mode and will turn on again, if the input is still high, after the measured temperature has dropped below the thermal hysteresis.

As per your saying, the device completely de-energies. Then this is normal behavior.

For your second question, can you please show how you have done the connection?

Thanks and Regards,
Anshika

[hardwareentw]

here an excerpt of the circuit diagram

[hardwareentw]

the module is not switched off in this thermal shutdown, but continues to conduct current. However, it can no longer be switched off and on.

The device does not switch off

[Anshika_G · Accepted solution]

Hello @hardwareentw ,

Can you please tell me from where have  you downloaded the simulation model of BTS4140N?
I cannot find this model on the website. 

Also, can you please measure the current value at IN pin?
I have tried simulating the model available with me with parameter Vbb =45V,  Tamb = 70 degree Celsius ,having a RL Load. The results shows that junction temperature crosses the 150 degree Celsius limit.  Hence, overtemperature protection will start and this might be one of the reasons the device is limiting the current to a suitable value and not allowing you to switch it further.  

I am sharing the simulation file with you. It is also available on product webpage, you can modify it accordingly.

Best Regards,
Anshika