DRV411EVM: The way to connect current sensor to DRV411EVM

Hello Chase.  
You are correct for the BOM being incorrect as the text mentions the correct part number "TQPL100A" and also mentions the 2000 turns ratio.  The TIPD184 also mentions the additional voltage drive requirement.

For the connections you need the hall sensor connections as well that are not shown in the image.  If the output rails you have a positive feedback loop so either reverse the connection of the compensation coil connections or flip the orientation of the hall sensor.

Regards,

Javier

Dear Javier,

Thank you for your support.

I have other questions.

My customer bought TQL50A samples from Topstek. and disassembled image is as below.

As you see there is hall device in the gap of magnetic core.

Could you check that how can I connect TQL50A to DRV411 EVM?

(I am asking it because it seems that TQL50A(the only sensor I can buy) and TQPL50A(the sensor which referred in the EVM) are different.)

And here are more questions;

- Could you find the difference between TQL50A and TQPL50A?

- What is the reason of schematic difference between TIPD180(±50A current sensor) and TIPD184(±100 A Closed-Loop Current Sensor)?

DRV411 is the same, but TIPD184 has op amp and 2 TRs.

-- TIPD180(±50A current sensor) Schematic

TIPD184(±100 A Closed-Loop Current Sensor) Schematic

Please check these issues. Thanks.

Best regards,

Chase

Dear Javier,

Thank you for your support.

Could you confirm once again about connecting TQL50A to DRV411EVM regarding to the pin map below?

https://webbuilder2.asiannet.com/ftp/1295/TQL50A.pdf

Best regards,

Chase

Chase,

This TQL50A  is a full sensor that has internal circuitry like the DRV411 that then outputs a current on M.  This does not connect to the DRV411.  I do not know the internal design of the TQL50A.  If you were to remove the hall sensor and coil you could connect it there like I showed in the schematic. 

Regards,

Javier

Dear Javier,

Thank you for your support.

My customer succeeded to test DRV411 EVM with TQL50A(Topstek).

Now they are planning to test the circuit which can measure current up to 250A.

1. Should my customer modify the schematic or change the value of any part of the EVM to measure 250A current?

2. Could you recommend the additional needed schematic and turn ratio for the core?

The core is made with Fe20Ni80(Permalloy) like below.

Best regards,

Chase

Dear Javier,

Thank you for your support.

Please let me know if there is an update about the issue above.

Best regards,

Chase

Hi Chase,

Javier is out of office and will respond when he returns on 11/6. Thank you for your patience.

Dear Javier, Holly,

Thank you for your support.

Please let me know if there is an update about the question above.

Best regards,

Chase

Hello Chase, 

Jumping in here; thank you for your patience. 

Just for confirmation, is this a unidirectional current sensing application for +250A or is it a bidirectional current sensing application for ±250A?

I would recommend adhering to this document (https://www.ti.com/lit/an/sboa136/sboa136.pdf?) for the correct number of turns where you will need to plug in the customers shunt resistor value. They will also need to size the shunt according to their downstream logic. 

I would also recommend that your customer implements external circuitry for sensing higher current as shown in TIPD184. 

The reason for the external circuitry is what Javier mentioned previously: 

Javier Contreras4 said:

The TIPD184 has external drive of the compensation coil to increase the compensation coil drive capability.  The two limitations are current or voltage and TIPD184 external amplifier and BJTs and higher votlage supplies to deals with both.  If the compensation coil resistance + Rshunt are too large you will need a higher voltage to drive it.  Or if the current you are measuring and the number of turns cannot be increased you may need a larger current to drive the compensation coil.  This design demonstrates how it can be done.

I hope this helps, 

Joe

Dear Joe,

Thank you for your support.

Current sensing range is ±250A RMS current, ±450A DC current.

Target sensitivity is 2.7mV/A.

1. It is okay to use OPA237 and TPS79850 in red box for ±450A DC current sensing application? or should I change for higher spec?

2. Could you recommend parts for T1,T2,D3,D4?

3. Customer calculated 19 ohm for shunt resistor. Could you check the calculation below?

4. Do you think 1500 turns are enough?

5. Can you expect the current through coil if customer us 1500 turns?

Best regards,

Chase

Hello Chase, 

Let me look into this and I will provide you with an update on Monday 11/17.

Thank you for your patience, 

Joe

Hello Chase, 

Chase Jeong said:

It is okay to use OPA237 and TPS79850 in red box for ±450A DC current sensing application? or should I change for higher spec?

Can you explain what you mean by "red box"? I would start with these devices for the additional output drive.

Chase Jeong said:

Could you recommend parts for T1,T2,D3,D4?

For D3 and D4, they can use BAT54S and for T1, they can use BCX56TA for T1 and they can use BCX53TA both from Diodes Inc.

Chase Jeong said:

. Customer calculated 19 ohm for shunt resistor. Could you check the calculation below?

Can you tell me where they got 3.175V across RSHUNT from?

Chase Jeong said:

Do you think 1500 turns are enough?

This value may change but theoretically, 1500 turns can work. 

Chase Jeong said:

. Can you expect the current through coil if customer us 1500 turns?

I suspect that with the additional external drive capability, it should be strong enough to drive the 1500 turns. I see that TQL50A is 1000 turns. Is your customer going to use a different turn ratio and part?

Best Regards, 

Joe

Dear Joe,

Thank you for your support.

1. The red box what I mentioned is as below.

2. Customer got 3.175V across RSHUNT because their target output voltage is 1.825V ~ 3.175V. (maximum value)

Please check these 2 issues.

Best regards,

Chase

Chase,

Thanks for your patience. Joe is out of the office today and will reply when he returns on Friday, 11/21.