DRV8323: Power Supply

Alvin Zheng

Part Number: DRV8323

Hi, Team

One question on the power supply to DRV8323. In the customer system, they will have separated power supply to IC and motor.

Is this allowed on DRV8323? What's the maximum voltage gap allowed between VM and VD shown as below?

What's the requirement on power up sequence for VM and VD?

over 7 years ago

0 James Lockridge19 over 7 years ago

TI__Genius 14487 points

Hi Alvin,

Please see this other post I answered recently:

e2e.ti.com/.../712365

Let me know if there are follow-up questions.

0 James Lockridge19 over 7 years ago in reply to James Lockridge19

TI__Genius 14487 points

Alvin,

As for power-up sequence, I would power the DRV8323 first before powering the H-bridge.

0 Alvin Zheng over 7 years ago in reply to James Lockridge19

TI__Intellectual 900 points

Hi, James

Please confirm my understanding is correct:

If separated VD(to IC) and VM(to motor) are applied, when turning on the high side MOSFET, SHx will be around VM, while GHx will be VD+10V. The breakdown of Zener diode is 16V. If the voltage gap between SHx and GHx exceeded the breakdown voltage, Zener will cause additional current flow path.

You also mentioned there are concerns on VDS monitor. Could you please offer more details about this? Also, will this affect VGS monitor?

Thank you.

0 James Lockridge19 over 7 years ago in reply to Alvin Zheng

TI__Genius 14487 points

Alvin,

Your statement about VM and VD supplies is correct.

My concern about the VDS monitor in the other post was related to the poster's question about using separate supplies on each half bridge. I think you shouldn't have an issue with your application if VDRAIN is connected to the VM bridge supply. This should not impact the VGS monitor.

The charge pump power is derived from the VD supply, so I would recommend VM and VDRAIN to be less than VD. If VM > VD, then the high-side FETs may not turn on.

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DRV8323: Power Supply