AMC1311

manoj r

Other Parts Discussed in Thread: AMC1311

We are using AMC1311 for DC Link Voltage Sensing. With inverter switching and loaded conditions we observed the output of AMC is picking the switching frequency component. Without PWM pulses the output is constant. What may be the reason for the same ???

over 4 years ago

0 kai klaas69 over 4 years ago

Guru 140200 points

Hi Manoj,

sounds like the anti-aliasing filter is missing at the input of AMC1311 (RF and CF of the simplified schematic on the frontpage of datasheet). And don't forget to use a differential ampflifier at the output of AMC1311 as shown in figure 50 of datasheet.

Kai

PS: Wanted to post two pictures here, but wasn't possible :-(

0 Alexander Smith over 4 years ago

TI__Guru 56872 points

Hi Manoj,

As Kai said, the anti-aliasing filter may be missing, or the high side ground may be connected incorrectly. Please share the schematic for further analysis.

0 manoj r over 4 years ago in reply to Alexander Smith

Intellectual 260 points

Hi,

Please find the schematics which we have used.

0 kai klaas69 over 4 years ago in reply to manoj r

Guru 140200 points

Hi Manoj,

R183 is counter productive here. I would do it this way:

How looks the differential amplifier at the output of AMC1311B? Can you show a schematic?

Kai

0 Alexander Smith over 4 years ago in reply to kai klaas69

TI__Guru 56872 points

Hi Manoj,

I agree with Kai that R183 is unnecessary. I would also be interested to see if the measurement improves without the diodes that are parallel to the shunt resistor.

Amplifiers

Amplifiers forum

AMC1311