LM5069: Over-current / Short-circuit protection

Ali Tekin

Part Number: LM5069

Tool/software:

Hello, we are experiencing an issue with short-circuit protection of schematic below. Normally the overcurrent protection works fine, but when we short circuit the output switching MOSFET is broken.

Schematic

It seems that the gate and source voltage rising time is long. Below are the rising and falling graphs with gate connected.

Turn-On graphic

And below are the rising and falling graphs between out and gate pins without the mosfet connected.

4 months ago

0 Rakesh 4 months ago

TI__Guru** 102811 points

Hi Ali,

Is VBATT voltage dropping when you short circuit ? Can you share VOUT, GATE, TMR and input current during short circuit event. All in a single scopeshot using 4-channel oscilloscope.

BR,

Rakesh

0 Ali Tekin 4 months ago in reply to Rakesh

Prodigy 40 points

Hello, we used a battery pack which has a short-circuit protection, it can provide an instantaneous current of 300A. When we short circuit the output terminals, we can hear a pulse sound indicating that the BMS has cut off the output voltage after the mosfet is broken. There are also two TVS diodes connected in parallel to the input and output terminals. It is interesting that when we increased the shunt resistance to 10 milliohms, the MOSFET remained solid even though we made many short circuit attempts. We used this mosfet in other projects as well, normally it can handle huge currents.