DRV8873H-Q1EVM: Bulk capacitor issue

Cherry Zhou

Part Number: DRV8873H-Q1EVM

Hi team,

Here're 2 questions from the customer may need your help:

1) It is noted that the choice of bulk capacitor also greatly affects the overall EMC and response performance. The selection of this capacitor is not detailed in our documentations and the customer would like to know how the design value is calculated.

2) What is the value of V(BR)DSS with built-in MOS? The customer is designing it to work in PWM mode. If both OUT1 and OUT2 are required to be Hi-Z after the external motor has started and operated for some time, the motor's back EMF can impact the chip and cause damage to the DRV8873H.

Also, can an energy storage device be introduced outside OUT1 and OUT2 as a buffer in the above cases? Is there a reference design recommendation for the respective energy storage device?

Could you help check this case? Thanks.

Best Regards,

Cherry

over 3 years ago

0 Jacob Thompson over 3 years ago

TI__Mastermind 23431 points

Hello Cherry,

1) The bulk capacitance is highly dependent on your system and the motor/application. You can read more on choosing a value for it here: Input and Output Capacitor Selection

2) This link discusses VM pumping and voltage rating margins, I think it might help answer this question: The art of stopping a motor – VM pumping

The bulk capacitor is the only standard energy storage device in this type of system. Another idea/method would be something like a custom regenerative braking circuit, but we don't have a reference design for that.

Regards,

Jacob

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DRV8873H-Q1EVM: Bulk capacitor issue