DRV8353: DRV8353- same gate drive current strength, but MOS-GS rise waveform is different

Hello,

Is there more capacitance at the HS MOSFET gate than LS MOSFET gate? Slower turn on times for one FET vs. another one means either smaller gate current (higher impedance in gate drive path) or added input capacitance at gate (Cgd, Cgs). Could be parasitic capacitance as well, do the HS MOSFETs have a longer gate path than the LS MOSFETs?

Regards,

Yara

thanks

-i don't adding more capacitor or resistor in high-side mos,the schematic is same

-check the pic as follows: you can see

1:the time of Vgs rising from zero to Miller plateau  is almost same  , so we can get the parastic capacitance is almost same---

2:the difference is the time taking on Miller region,  the waveform of high-side mos Miller plateau has a little oscillation--

pls check again ,thankyou 

Hello,

Can you please provide what MOSFETs you are using?

Thank you,

Yara

hi

the MOS type:  IPT012N08N5, I have referred in my PPT above

thankyou

Hello Robin,

Are you using any clamping diodes in your system?

Regards,

Yara

hi

I didn't add any thing 

plz check the following sch

SCHEMATIC1 16_DRV.pdf

thanks   Looking forward to good news

Hello,

After reviewing your schematic it seems like your VDRAIN to VCP connection might not be optimal. Using the EVM schematic is a pretty good way to verify a few things in your own schematic. 

VDRAIN goes directly to VCP and does not connect to VM (it may seem like this but it does not share a node with VM), after fixing this see if the issue persists.

Regards,

Yara

sorry， I did not find what‘s different from EVM,in  EVM ,the VDRAIN is also connected to VM’

also VM can be powered from 2 ways, one is from Motor supply ,another is from a low voltage , in my sch,  VM is powerd from Motor Supply

pls help me check again

Hello,

Have you been able to resolve your issue? If so please press the "This resolved my issue" button to any of the answers.

If you have any other additional questions please feel free to post another E2E question, other wise I will be closing this thread.

Regards,

Yara