DRV8343-Q1: PSpice model doesn't contain necessary pins

Hi Rajeev,

DRV8343-Q1 PSPICE model only includes the gate drive outputs for a single independent half-bridge. It does not simulate the CSA performance. 

We need time to confirm with systems the COMP_BOB functionality. 

Thanks,
Aaron

Hi Aaron,

     thank you for your response.  How may I best simulate the performance of the CSA of the DRV8343?  In particular, I want to know how an input-filter will affect accuracy.

Regards,

Rajeev

Hi Rajeev, 

If PSPICE sim model doesn't have coverage for the CSA input filtering, it is still possible to evaluate the impact of CSA input filtering both theoretically and experimentally. 

In general, the below two points should be true: 

1. CSA input filtering will help reduce/mitigate the noisy transients observed from the motor current feedback across the shunt resistor 
2. the input filtering capacitors will take time to charge and discharge, so there will have to be some consideration in your ADC's sampling intervals to give the CSAs and capacitors some amount of 'settling time' in order for the measurements to be accurate

The below resources should also help: 

• Previous E2E thread: https://e2e.ti.com/support/motor-drivers-group/motor-drivers/f/motor-drivers-forum/1069811/drv8353rh-evm-drv8353-source-pin-resistor-filtering-and-layout-guidelines
• TIPL video: https://training.ti.com/ti-precision-labs-current-sense-amplifiers-input-filter-error
• Layout Best Practices: https://www.ti.com/lit/an/slva959b/slva959b.pdf
  • (proper PCB placement, grounding, and component selection will also be important for CSA performance) 

Please advise if the info is able to answer all your questions, and let us know if any further support is needed. 

If possible, also help mark the thread as 'resolved' if complete. Thanks! 

Best Regards, 
Andrew 

Hi Andrew,

     I have reviewed the linked E2E thread and TIPL training video in addition to the layout "best practices" app. note.  Those sources of information do not satisfy my analyses, so I am hoping to simulate the problem.  At least, can you inform me of the CSA topology for the DRV8353 and the value of the input resistors of the CSA?

Thank you,

Rajeev

Hi Rajeev, 

I'll follow up with the team to see if we are able to provide the information requested 

Will aim to get you a response before end of week at latest 

Best Regards, 
Andrew 

Hi Andrew,

     thank you.  The DRV835x datasheet provides surprisingly little information regarding the specifications of the CSA.  Since the CSA is an important component of the device's architecture, designers need to know its characteristics.

Regards,

Rajeev

Hi Rajeev, 

I aligned w/ my team members on this topic, but the latest internal discussion suggests that we may not be able to share this information publicly

Best Regards, 
Andrew 

Hi Andrew,

     in this case, how does TI recommend one to design the input filter to the PGA for a given application?

Regards,

Rajeev

Hi Andrew,

     thank you for the additional useful information.  The link that you just provided for the DRV8343 that includes the desired resistor values for the CSA shows a (slightly) different circuit than the one included in the latest datasheet - FYI.  Since I am using the DRV8353, will you please confirm the resistor values for the CSA used in that device?

Regards,

Rajeev

Hi Rajeev,

We will try to get back to you by the end of the week.

Regards,

Anthony Lodi

Hi Rajeev, 

just wanting to share an update here - I have been discussing this info w/ the design team this past week, and am hoping to get an answer to share within the next few days, specific to DRV835x.

Best Regards, 
Andrew