DRV8962EVM: DRV8962EVM

Hi Santhosh,

Yes, the PWM inputs should match the outputs. 

I have the following two suggestions.

First, verify all connections are correct. From the scope capture it appears the device is being enabled and disabled from the IN1 pin. When the PWM input goes high the outputs are allowed to switch and when it goes low the outputs are disabled. 

Secondly, I would suggest verifying normal operation on the EVM first using the GUI?

Best,

David 

Hello David,

I verify all the connections are correct, I check the output with connecting any load. it is working. Can see the TOP switching is ON. But When connect the Resistive load. it is not behaving same as yesterday.

I checked with same OUT2 and second board with OUT1 & OUT2. Issue will be the same.

could you please help me on resolving this.

No load PWM switching.

Thanks,

Santhosh

Hi Santhosh,

It is likely that the ITRIP value is not high enough. It appears that the load current is hitting ITRIP causing outputs to disable for tOFF. 

How is current regulation being configured?

See the datasheet link below for more information on Current Regulation. 

DRV8962 Four-channel Half-Bridge Driver with Current Sense Outputs datasheet (Rev. B) (ti.com) 

Section 8.1.1.3 Application Performance Plots shows a scope shot that is similar to what you are seeing.

Best,

David

Hello David,

We are not uisng the current sense output we disable it we have shorted the J17. 

I found the issue it is with Vref, If we disable the IPROPI we need to provide Vref value more than GND. 

As we are modifying the board as per our convenance. 

Could you please suggest me, Can we connect short DVDD to vref, Already we are shorting the DVDD to VCC, nsleep, EN1,, So if Add vref also to DVDD it will be a problem or not?

To short DVDD to VCC and other pins, we are cutting 3.3V track to eliminate the power to Micro controllers, those are discussed previously in the forum.

Thanks,

Santhosh

Hi Santhosh,

I am happy to hear that you solved the issue. 

There should be no issue with using DVDD to supply VREF.

Best,

David

Hi David,

Thanks for the information, I read the datasheet. But my concern if I short the VCC,Nfault, EN1 & Vref with DVDD. It will be work right? There will be No loading on internal LDO right?

Best,

Santhosh.

Hi Santhosh,

Please allow me another day to look into this. I will reach out to you when I know more.

Best,

David

Hi Santhosh,

I was not able to get to this today, but I will try to replicate this in the lab and get back to you on Monday. 

Best,

David

Hi Santhosh,

Tying EN, VCC, and VREF to DVDD is ok to do with this device. The only issue is if nSLEEP is tied to DVDD the device will never exit sleep mode. For this reason, nSLEEP should not be tied to DVDD. 

Best,

David

Hi David,

Thanks for the information, I am not tying the nSLEEP with DVDD instead of sleep pin I am tying nFAULT pin.

Can you please conform the same.

Thanks,

Santhosh

Hi Santhosh,

Sorry for the confusion. 

Yes, you should be able to connect these pins to DVDD with no issue. 

Best,

David