L6398 Problem

[Vnguy.1]

Hello my Friends.

Please help me.

I got a problem with L6398 for bldc driver.

the above picture is 1 phase for bldc driver using L6398 and FR3607. After I got PCB and soldered it. But when I tested it, I got the problem as:

Here is the truth table of L6398

when I set LIN = H, HIN = H then LVG = L, and HVG = H. it is ok.

when I set LIN = L, HIN = L then LVG = H, and HVG = L. it is fine.

But when I set LIN = H, HIN = L (or LIN = L, HIN = H) then LVG = L, and HVG = H.

I tried to solve it, until now I can not, and I don't know the reason for my problem.

Please help to fix this problem.

Thank you so much.

Keep safe.

[Cristiana SCARAMEL]

Hello @Vnguy.1​,

Please not that the HVG signal must be referred to the OUT voltage, are you using a differential probe to monitor the HVG versus OUT voltage?

Otherwise you can measure the HVG and OUT signals versus ground (pay attention to the max voltage of the probes) and use a mathematical function to derive the "HVG-OUT" voltage.

Could you share some oscilloscope waveforms of the inputs and outputs signals?

The signal probes placed directly on the device pins or as close as possible to the device.

I look forward to your feedback for more detailed support.

[Vnguy.1]

Hi Cristiana

I am checking another problem from My PCB. Power for stm32f is not stable. So I guess it led L6398 worked not correctly.

Therefore, after I check my PCB, then test again. Then if there is any problem with L6398, I will provide information to you

Thank you so much

[Cristiana SCARAMEL]

Hello @Vnguy.1​,

any news about your issue?

Please share with the Community your progress.