AMC1311: 3Phase-3Wire voltage measurement

ali kelem

Intellectual 400 points

Part Number: AMC1311
Other Parts Discussed in Thread: AMC1336, DAC53401

Hi,

A customer request a 3Phase-3Wire (no neutral) 250VAC/60Hz isolated voltage measurement device.

I'd like to ask if AMC1311 is suitable for it as seen drawing.

(sorry for bad drawing, AMC1311 would have diff. output)

Thanks.

over 5 years ago

0 kai klaas69 over 5 years ago

Guru 140200 points

Hi Ali,

yes, should work.

Kai

0 Alexander Smith over 5 years ago

TI__Guru 55062 points

Hi Ali,

This should work, but one thing to keep in mind is that the input voltage range of the AMC1311 is 0-2V. This device is primarily meant for DC voltage sensing applications.

There are two things that can be done here.

1. Consider using the AMC1336. This device is an isolated modulator with a high input-impedance +/-1V input range.

2. Consider using a buffered 1V reference to shift the input range up by 1V. This will allow the measurement to swing +/-1V within the 0-2V input range. I've attached a TINA schematic that shows this implementation.

Please let us know if you have any additional questions. AMC1311_BipolarInputs.TSC

0 ali kelem over 5 years ago in reply to Alexander Smith

Intellectual 400 points

Hi Alexander,

Thanks for your help.

I think, will use AMC1311 and buffered&shifted 1V solution as seen your TINA file.

Prefer to work in analog domain.

One more question;

Customer ask me if input frequency range can be up to 600Hz.

If I use AMC1336, its Delta-Sigma Mod. will succeed it?

Regards.

Ali

0 ali kelem over 5 years ago in reply to kai klaas69

Intellectual 400 points

Thanks Kai.

0 kai klaas69 over 5 years ago in reply to ali kelem

Guru 140200 points

Hi Ali,

don't forget to mount protection diodes at the output of U1 to protect U1 in the event the OPAmp isn't yet powered.

Another option is to use a passive voltage divider for biasing the input of AMC1311.

Kai

0 ali kelem over 5 years ago in reply to kai klaas69

Intellectual 400 points

Hi Kai,

As I understand, you mean such a circuit as below?

Left one : protected opamp in event not powered.

Right one : Passive DC bias

Thanks.

Ali

0 Alexander Smith over 5 years ago in reply to ali kelem

TI__Guru 55062 points

Hi Ali,

Did you mean 600kHz?

AMC1311 and AMC1336 can both handle 600Hz. The AMC1311 will not be able to properly sense 600kHz because of the integrated digital filter.

The AMC1336 can sense 600kHz but it will have a lower resolution measurement, this ultimately depends on the choice of digital filter.

This document may be helpful, it shows the tradeoffs of isolated amplifiers vs isolated modulators: http://www.ti.com/lit/wp/sbaa359a/sbaa359a.pdf

0 kai klaas69 over 5 years ago in reply to ali kelem

Guru 140200 points

Hi Ali,

yes.

Kai

0 ali kelem over 5 years ago in reply to Alexander Smith

Intellectual 400 points

Hi Alexander,

Thanks for your support.

I'll use AMC1311 in project.

Regards.

Ali

0 ali kelem over 5 years ago in reply to kai klaas69

Intellectual 400 points

Hi Kai,

Thanks for your help.

Regards.

Ali

0 Alexander Smith over 5 years ago in reply to ali kelem

TI__Guru 55062 points

Hi Ali,

Great to hear! Please let us know if you have additional questions.

0 ali kelem over 5 years ago in reply to Alexander Smith

Intellectual 400 points

Hi Alexander,

You had recommended to shift 1V reference at input of AMC1311 in previous messages.

And, you had sent me a TINA circuit "AMC_bipolarInputs.TSC"

I want to control 1V by software and will be using buffered DAC53401.

So, I changed the circuit as below.

Do you have any recommend?

Thanks.

Ali

0 Alexander Smith over 5 years ago in reply to ali kelem

TI__Guru 55062 points

Hi Ali,

Thank you for starting a new thread. I will post my response there: https://e2e.ti.com/support/amplifiers/f/14/t/878318

Amplifiers

Amplifiers forum

AMC1311: 3Phase-3Wire voltage measurement