DRV3946-Q1: External devices when using low side driver with high side switch: TPS1HTC30-Q1

Jessica Riley

Part Number: DRV3946-Q1
Other Parts Discussed in Thread: TPS1HTC30-Q1, , TPS1H100-Q1

Tool/software:

Hello,

I am planning to use the high side switch TPS1HTC30-Q1 with low side driver DRV3946-Q1 (the high side switch being shared between the two loads).

My question is what external clamping/protection devices should be included when using this combination of parts.

The TPS1HTC30-Q1 datasheet suggests using a resistor+diode network from device ground to board ground to clamp negative voltage transients, but is that necessary given the internal clamping of the DRV3946-Q1 low side switches?

I have reverse polarity protection on my input supply, so I am only concerned about transients on the output loads.

My current is 1.5A max continuous w/ 10A peak pick-up current (<250ms). Operating voltage is 35V max.

over 1 year ago

0 Ibinu Alaudeen Nadeera over 1 year ago

TI__Genius 11781 points

Hi Jessica,

Thanks for the question.

For the normal turn OFF of the device, we have QTO feature in the DRV3946-Q1 which will give a clamp and path for inductive current discharge.

However for the condition that the high switch turn Off, with the low side QTO, a diode from PVDD to GND will be needed as shown in D1 in the following diagram

Please let me know if this clarifies the question.

I will be happy to review the schematic of the design in case that is needed.

Thanks,

Ibinu

0 Jessica Riley over 1 year ago in reply to Ibinu Alaudeen Nadeera

Intellectual 480 points

That makes sense in terms of the need for the free-wheeling diode. With that diode, it seems like the RGND and GND recommended for the TPS1H100-Q1 high side switch should not be required - right?

+1 Ibinu Alaudeen Nadeera over 1 year ago in reply to Jessica Riley

TI__Genius 11781 points

Hi Jessica, Yes that would be correct.

Thanks,

Ibinu

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DRV3946-Q1: External devices when using low side driver with high side switch: TPS1HTC30-Q1