TPA3111D1, TPA3112D1 over current protection threshold

Rowan Diskin

Other Parts Discussed in Thread: TPA3112D1, TPA3111D1

Hi,

I am using the TPA3111D1 to drive a predominantly inductive load. The design is based upon the EVM board, with an LC filter, and with -SD and -FAULT linked for automatic recovery. On the datasheet there is no figure for the current threshold at which the over current protection kicks in on this IC. I've successfully managed to get about 2.6Arms at 1kHz sine. The application requires a current of at least 2.4Arms, more would be desirable, obviously I'm running quite close to the limit.

If such a thing exists, I'd like to know a MIN/TYP/MAX figure for the over current threshold on the TPA3111D1. It would also be useful to know if this threshold is higher on the 25W chip, the TPA3112D1.

Regards,

Rowan.

over 13 years ago

0 Curt Stephens over 13 years ago

TI__Expert 4410 points

Rowan, the current limit can be calculated through the "back door" by looking at the minimum impedance specs. The device supports a minimum of 3.2 ohms up to a supply voltage of 15V. If you add the rds,on times 2 and liltte series R for the filter inductors, you will arrive at the peak current of around 4A. The overcurrent protection circuit operates on the peak current and limits at 4A nominally.

Let us know if you have any further questions or comments.

Curt

0 Curt Stephens over 13 years ago

TI__Expert 4410 points

Rowan, as for your second question, the 4 A number is typ and the spread with process and temp is approximately 0.5A. The TPA3112 has the same OC threshold as the TPA3111.

Regards,

Curt

0 Rowan Diskin over 13 years ago in reply to Curt Stephens

Prodigy 40 points

Thanks for your help Curt,

I'll feedback if I have any more queries in this matter.

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TPA3111D1, TPA3112D1 over current protection threshold