TIDA-01606: Current sensing technology and location

Téo Robert

Part Number: TIDA-01606

Hi,

I am designing a T-Type converter based on the TIDA-01606 reference design, and I am worried about current sensing.

I noticed on the forum and design guide that hall effect sensing on the inverter side has issues with layout noise on the current design (phase A is sometimes spectifically mentionned which makes sense due tu longer signal path).

1) I am wondering if the issue is still present in the current design.

2) Considering the noise issue, couldn't the current sensor be placed on the other side of the inductor away from switching nodes ?

3) Considering the two technologies (shunt+SDM and hall effect) proposed in the ref design, would you recommend one or the other ? I also considered TMR/AMR SOIC sensors for my application.

Thanks in advance,

Téo Robert

8 months ago

0 Riccardo Ruffo 8 months ago

TI__Intellectual 2600 points

Hi Robert,

1)yes you are right the current sensor located in the switching node are having issues due to the high dv/dt presented by the SiC device.

The current reference design is working by using the solution based on delta sigma.

2)yes, if you place the sensor on the other side of the inductor you will be able to remove quite a lot of noise there.

3) You could use both the delta sigma and the hall effect ones. You can find newest TI devices for sensing current in the following link:

https://www.ti.com/sensors/magnetic-sensors/hall-effect-current/products.html

Furthermore, if you would like to have a more deep understanding about accuracy, offset etc you can give a look to the following document.

https://www.ti.com/lit/an/sbaa541/sbaa541.pdf?ts=1706631855503&ref_url=https%253A%252F%252Fwww.ti.com%252Fsitesearch%252Fen-us%252Fdocs%252Funiversalsearch.tsp%253FlangPref%253Den-US%2526searchTerm%253DDesign%2BConsiderations%2Bfor%2BCurrent%2BSensing%2Bin%2BDC%2BEV%2BCharging%2BApplications%2526nr%253D686

Thanks

Best Regards

Riccardo

0 Téo Robert 8 months ago in reply to Riccardo Ruffo

Prodigy 100 points

Hi,

Thanks for the answer and the document, it is very helpful.

Concerning the TI hall effect sensors you linked, I am wondering what are their drawbacks compared to the bulky LEM CASR 15-NP current transducers used in the reference design, as they seem to be smaller, cheaper and have a higher bandwidth and good isolation.

Thanks in advance,

Téo Robert

0 Riccardo Ruffo 8 months ago in reply to Téo Robert

TI__Intellectual 2600 points

Hi Robert,

i am not seeing any drawbacks in the new current sensors. Actually, they even present higher CMTI.

THanks

Best Regards

Riccardo

0 Téo Robert 8 months ago in reply to Riccardo Ruffo

Prodigy 100 points

Hi,

Thanks for your answer. I have an additional unrelated question concerning TIDA-01606.

I notices in the design files that there are variants in the schematics for which I don't know the reason. I assume the 001 is a default variant ?

For the powercard : variants 001 and 072318 with slight changes, notably grid and inverter voltage measurement (DNP resistors on voltage reference OP amps outputs). 072318 only differ from 001 by DNP on input filter.

For the HV sensing card : only one variant 001 with DNP R8, R28 and C23. Does it means they should not be connected by default ?

For the Gate driver card : only one variant with no significant changes (coaxial connectors DNP).

Could you clarifiy the purpose of those variants ?

Thanks in advance.

Best regards.

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TIDA-01606: Current sensing technology and location