DRV8343-Q1: dead time

Hi Ivy,

It looks like the customer has both high side and low side turned on at the same time.

Are they using SPI or Hardware variant?

What is their deadtime?

What IDRIVE settings is the customer using?

Are they using Independent Half-Bridge PWM Mode?

Can you give a little more background on when they are seeing this shoot through event? and whether they've seen damage to the driver or FETs?

Regards,

Yara

Hi Yara,

Please see below feedbacks.

1. The customer used the SPI version.

2. The DEAD_TIME is the default value of 1000ns,the customer attempted to modify the dead time through SPI, but found that it could not be modified successfully.

3. The IDRIVE setting is 1A for all 6 channels.

4. PWM_MODE = 000b，6x PWM mode

5. Waveform measurement method: Two MOS gate in phase A measured via oscilloscope; no damage to drive and FET 

 Thanks!

Regards,

Ivy

Hi Ivy,

Is GHx being measure from GHx to GND or GHx to SHx? If not please have the customer measure with respect to SHx.

Regards,

Yara

Hi Yara,

1, The previous waveform is the GHX to GND waveform.
2, GHx to SHx test waveform as below, from the waveform can be seen, the high side MOS open will cause the low side MOS to appear voltage spikes.

Regards,

Ivy

Hi Ivy,

So it looks like no shoot through is happening, it is important to look at GHx to SHx when trying to view something like deadtime. I think those spikes might be present because the customer is using 1A for IDRIVE. 1A might be too much for the FETs they are using since the Qgd is 22nC.

Please refer to the following FAW to select the best IDRIVE setting for their system:

https://e2e.ti.com/support/motor-drivers-group/motor-drivers/f/motor-drivers-forum/796378/faq-selecting-the-best-idrive-setting-and-why-this-is-essential

Once they've lowered their IDRIVE settings feel free to send updated waveforms for my to analyze if need be.

Regards,

Yara