INA199

zevi kramer35

Other Parts Discussed in Thread: INA199, INA301

we are getting a 5-10microSEC pulse on the output when we connect the load. The peak of the spike is 3-4 times what is expected by calculation. After the 5-10microSEC the INA199 opeartes as expected.

1) How can we avoid having this spike?

2) can we use the INA199 as a feedback to a current limit (PWM)?

thank you

zevi

over 8 years ago

0 Carlos Silva85 over 8 years ago

TI__Expert 4915 points

Hi Zevi,

Thank you for posting on the E2E Foruns.

The INA199 requires a blanking time at startup. Our own tests have shown the device can peak for up to 30uS under some circumstances, when used as a low side sense. The peak is normally not directly related to the measured current, so you would not be able to calculate it.

Can you elaborate more on current limit feedback required? Cycle by cycle or average? What would the required response time be? What is the PWM frequency?

0 zevi kramer35 over 8 years ago in reply to Carlos Silva85

Prodigy 50 points

got it thank you.
1. we are using the INA199 on the high side with 50:1 gain.
2. regarding : current limit: cycle by cycle. required response time less 20microSEC,
what do you see possible?

thank you
zevi

0 Carlos Silva85 over 8 years ago in reply to zevi kramer35

TI__Expert 4915 points

Hi Zevi,

I would suggest the INA301. It has a dedicated output that can be used to halt the PWM.

0 zevi kramer35 over 8 years ago in reply to Carlos Silva85

Prodigy 50 points

got it carlos thank you!

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