DRV3946-Q1: current ripple is too large

Amber Si

Part Number: DRV3946-Q1

Tool/software:

Hi team,

Customer have two DRV3946-Q1 to drive 4 relay coils(PC is 400mA, HC is 240mA, PWM Frequency Settings is 2k ), and they only control 1 channel to drive coil, the current ripple waveform and OUT waveform is normal as below:

But when they open 2 or 4 channels at same time, current ripple will be larger at any channel, seems different channel are interfering with each other, as you can see the abnormal PWM waveform:

first DRV3946's OUT2 and second DRV3946's OUT2 have been controlled:

All the 4 channels are turned on:

Not sure how we can deal with that? I doubt there is something wrong in PCB layout leading to interference.

Schematic and layout will be attached for your reference.

Amber

5 months ago

0 Keerthivasan Kumanan 5 months ago

TI__Mastermind 18365 points

Hi Amber,

Could they also measure the IPROPI voltages for all the cases you have listed above. I am reviewing everything and will feedback by tomorrow. Can you let me know who the customer is and what their application is?

Best,

Keerthi

0 Amber Si 5 months ago in reply to Keerthivasan Kumanan

TI__Intellectual 2115 points

Hi Kumanan,

My customer is Huizhou EVE, customer found PCB layout issue about larger GND loop area which can affect PWM and ripple, and they plan to re design PCB layout, I'll get back to you if further update. Thanks

Amber

0 Keerthivasan Kumanan 5 months ago in reply to Amber Si

TI__Mastermind 18365 points

Hi Amber,

What do you mean by larger GND loop area?

Which pin are we talking about here?

I will wait for your update.

Best,

Keerthi

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DRV3946-Q1: current ripple is too large