INA228: INA228 High Voltage Measure

Corrado Corradi

Prodigy 40 points

Part Number: INA228
Other Parts Discussed in Thread: AMC1400, AMC23C14

Hi,

I'm looking for solution to measure a current at high voltage up to 2,5KV.

Current will be very low, about uA.

Can I use the INA228 with I2C isolator or a similar solution?

Thanks

Corrado

over 1 year ago

0 kai klaas69 over 1 year ago

Guru 140200 points

Hi Corrado,

have you thought about using an isolating amplifier?

https://www.ti.com/isolation/isolated-amplifiers/products.html

Kai

0 Corrado Corradi over 1 year ago

Prodigy 40 points

Very good solution.

I don't understand if AMC1400 is able to work at 2500VDC.

The relevant parameter is VIOWM DC at 2800V. It is Right?

Corrado

0 Mitch M over 1 year ago in reply to Corrado Corradi

TI__Genius 17990 points

Hello Corrado,

Yes, you can use the INA228 with an I2C isolator. Here is an example with a similar device that could be adapted to the INA228: https://www.ti.com/tool/TIDA-01608.

Regards,

Mitch

0 kai klaas69 over 1 year ago in reply to Corrado Corradi

Guru 140200 points

Hi Corrado,

yes. See also figure 6-4 of datasheet of AMC1400.

Kai

0 Corrado Corradi over 1 year ago in reply to kai klaas69

Prodigy 40 points

Hi,

OK for measure.

The circuits should be like picture attached.

At the moment I'm wondering how to protect the circuits when MOS damage occurs (like a short to GND).

May be a simple zener paralleled to sensing resistor and a fuse can protect everithing?

Corrado

0 Mitch M over 1 year ago in reply to Corrado Corradi

TI__Genius 17990 points

Adding the team that supports the AMC1400 for further support.

0 kai klaas69 over 1 year ago in reply to Corrado Corradi

Guru 140200 points

Hi Corrado,

this cannot be answered without knowing the whole circuit and all relevant design details like power-up and power-down chracateristics of 2.5kV high voltage for instance.

Kai

0 Alexander Smith over 1 year ago in reply to kai klaas69

TI__Mastermind 47625 points

Hi Corrado,

Kai has made the correct recommendation from the precision data converter side. AMC1400 is capable of withstanding this high voltage as shown in figure 6-4 and the VIOWM specification as you've pointed out.

As for protecting the circuit, this is a complex issue and depends on a variety of factors - many dependent on the end equipment application. What is this circuit to be used for? Can you share a larger block diagram?

We have isolated comparators AMC23C14 for example, with very fast response time (500nS) that can be used to protect MOS during short circuits. These devices however come in a smaller package and have a VIOWM of 1060V_DC.

+1 Corrado Corradi over 1 year ago in reply to Alexander Smith

Prodigy 40 points

Hi,

I'm working as designer of Testing Application.

Our customer are looking for an application that can able to measure IDSS current of a MOS with VDRAIN up to 2.5KV.

The base circuit is like the shared pictures and I think that for the mesure the problem is solved by AMC1400.

I immagine that during trials (that can go on also for 1000hrs) a damage of MOS can occurs and I must design shomething that prevent the damage of mesure circuits. AMC23C14 could be a good solution to turn off the VHIGH supply when a short occurs for example.

Obviously it depend to time response and time to short of MOS under Test. i'm sorry but I have no other data to share with you.

However everithing should be tested by a prototype circuits.

Thank for your support.

Corrado

0 Alexander Smith over 1 year ago in reply to Corrado Corradi

TI__Mastermind 47625 points

Hi Corrado,

Thank you for the background. Please post on E2E again for schematic review or any additional questions you may have.

0 kai klaas69 over 1 year ago in reply to Corrado Corradi

Guru 140200 points

Hi Corrado,

the usual way to experiment with high voltage sources is to have a current limiting protection resistance between the high voltage source and the target. In your case a 1M current limiting protection resistance made of ten 100k resistors in series would make sense.

Kai

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INA228: INA228 High Voltage Measure