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DRV8301: Separate power supply to 3-phase bridge driver

Jan Bock
Intellectual 2840 points
Part Number: DRV8301
Other Parts Discussed in Thread: DRV8353, , DRV8323, DRV8350

Hi Team, 

can you please have a look on the following customer inquiry: 

We have bridge drivers DRV8301, DRV8323 and DRV8353 in use in our products. The devices have separate power supply pins for logic and motor power from the outside.

I only find in the data sheet of the DRV8353 the statement that VM and VDRAIN may come from different supplies, since the charge pump regulates with reference to VDRAIN. What about the DRV8301 and DRV 8323 types? On the DRV8301, PVDD1 is at +24V_Logic. This voltage is independent of the DC link voltage.

The DC link voltage can also be 0V if the voltage at the "Motor power" connection has been removed while +24V_Logic is still present (max. 30V). On the DRV8323, the VM is connected to +24V_Logic via diodes or to the DC link voltage, depending on what is higher. VDRAIN is of course connected to the DC link. Here, the DC link voltage can also be 0V if the voltage has been removed at the "Motor power" connection, while +24V_Logic is still present (max. 30V).

Do situations arise in which the gate-source voltage for the high-side FETs becomes too high or is there a protective mechanism here?

I'm afraid that on the high side FET the gate source voltage will be over 30V when the DC link voltage is 0V, However, the bridge driver PVDD or VM is supplied. The charge pool generates the voltage in relation to PVDD or VM. Only on the DRV8353 the voltage of the charge pump is related to VDRAIN.

thanks 

Jan

  • +1
    TI__Mastermind 23005 points

    Hello Jan,

    Thanks for reaching out and posting to the MD forum. To answer your question the DRV8350 and DRV8353 are the only devices in which you can use a split supply, meaning VM and VDRAIN come from different supplies. We do not recommend this on the other devices you mentioned (DRV8301 or DRV8323), these devices are designed for VM and VDRAIN to operate at the same voltage. Running split supplies on these two may cause issues with the gate-source voltages as you mentioned  as well as the VDS monitors.

    I hope this helps!

    Best,

    Isaac