DRV8962: Separate half-bridge power supplies

Karen Leonard

Part Number: DRV8962
Other Parts Discussed in Thread: DRV8251A

The DRV8962 is suggested as a replacement for the EOL DRV8432. One nice feature of the 8432 is that it allowed for differing power supply values for each half-bridge.

Do any of the possible replacements have that same feature?

over 2 years ago

0 Jacob Thompson over 2 years ago

TI__Mastermind 23701 points

Hey Karen,

Do you mean the different PVDD_x supplies (A/B/C/D)?

Could you give a block diagram of what you're trying to accomplish? Trying to make sure I understand the question correctly. Are you wanting 1 half bridge to connect a load between +12V and GND, anther between +24V and GND for example?

Best,

Jacob

0 Karen Leonard over 2 years ago in reply to Jacob Thompson

Prodigy 45 points

Yes, that's exactly what I need ... let's see if I can insert a part of the schematic; the device is the DRV8432.

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0 Jacob Thompson over 2 years ago in reply to Karen Leonard

TI__Mastermind 23701 points

Hey Karen,

Is that in an existing design and working? Though the DRV8432 has separately labelled PVDD lines, we do not recommend using it in this manner as there is likely an internal connection between the PVDD connections. This should result in extra current within the device leading to thermal issues

None of our newer devices will support this mode. It is very difficult and space-intensive to implement this type of power supply separation within the silicon of a device. The best I can recommend is using separate half-bridge driver chips for each load voltage.

Regards,

Jacob

0 Karen Leonard over 2 years ago in reply to Jacob Thompson

Prodigy 45 points

Hi Jacob,

Yes, I believe it's been in use since 2019 (according to the pcba database). It works in a very small temperature window.

I was wondering how you could implement multiple power planes in silicon like that. Interesting.

Can you recommend a driver device that would work for the two motors? 24V and 12V. While the 8432 supports 6A per bridge, I think I really only need 2~3A. Another mystery as to why they chose such a large device.... Needs PWM capability, and internal current monitoring would be nice; I could get rid of some external circuitry. Thanks!

0 Jacob Thompson over 2 years ago in reply to Karen Leonard

TI__Mastermind 23701 points

Hey Karen,

Interesting, I'll try probing the pins on a DRV8432 device to see if they are internally connected or not.

Check out DRV8251A - up to 50V, 4.1A peak, PWM mode, has integrated current sensing, current regulation, and low-power sleep mode. Nice small 4.9mm x 6mm package, so 2x DRV8251A takes up much less space than DRV8432.

DRV8231A is rated up to 35V / 3.7A and comes in an even smaller 2mm x 2mm package and a lower price point. 35V should be fine for the 24V motor though I would make sure you have enough bulk capacitance. This might actually be better for your system overall if the 3.7A is enough for peak conditions.

Best,

Jacob

0 Karen Leonard over 2 years ago in reply to Jacob Thompson

Prodigy 45 points

Thank you for the recommendations! I had the DRV8251A on my list already.

One last question ... is there a contact within TI to talk to about a last time buy of the DRV8432?

0 Jacob Thompson over 2 years ago in reply to Karen Leonard

TI__Mastermind 23701 points

Hey Karen,

Please contact your TI sales team or field applications engineer (FAE) for that info. Unfortunately I do not have any information about it or if they are having different dates based on region or order size or anything.

Best,

Jacob

0 Karen Leonard over 2 years ago in reply to Jacob Thompson

Prodigy 45 points

Thank you for your help!

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DRV8962: Separate half-bridge power supplies