Hello, 

Thank you for your post. 

1. In the design, a 10 Ω shunt is used with the compensation coil, which is correct as per calculations. However, Appendix A mentions a parallel 1 kΩ resistor, making the total resistance approximately 9.901 Ω. Is this parallel network added solely for resistance correction?

   1. Thank you for pointing this out. This was meant to be a DNP for the 1k resistor.  

2. Regarding the 7th point "modification "in the document:
   To design a higher range closed-loop current sensor (±1500 A max), apart from adjusting the shunt resistor value and compensation coil turns/inductance, are there other factors to consider? Can the same PCB layout be used with just component value changes?

   1. You are correct for lower current applications. However, without additional circuitry, the DRV411 is not suitable for a 1500A application. Here is a similar post discussing said limitations: (+) DRV411: compensation coil resistance and inductance problem - Sensors forum - Sensors - TI E2E support forums
      1. Larger currents require more secondary windings and/or larger compensation currents.
      2. More secondary windings increase total resistance of the coil.
      3. Increasing gauge wire reduces coil resistance with the cost of a larger core.
      4. Increasing winding and increasing gauge wire may not be enough.
      5. Output drive of DRV411 can be increased with additional circuitry as shown in this post about the similar DRV421 here: https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/1035553/drv421-drv421-in--15v-applications 

1. Gain Selection:

   The IC provides three configurable gain modes:

   • Gain 1: 250 V/V, frequency 3.8 kHz
   • Gain 2: 250 V/V, frequency 7.2 kHz
   • Gain 3: 1000 V/V, frequency 3.8 kHz

   My doubts are:

   • On what parameters should the suitable gain mode be selected? The guide suggests starting with Gain 3, but what specific observations or tests should be made? what this gain means what is their role with respect to the compensation coil? The document mentions inductance and core size as critical factors. Are there additional parameters to consider, particularly for determining the gain when designing a wire-wound core. 
     
     • 
     • This gain essentially is part of the signal conditioning block that controls the Hall sensor spinning currents for the front-end of the DRV411. This is the gain setting applied to the sensed hall voltage and, using gain select, you can choose the appropriate gain setting to ensure loop stability over frequency. This gain setting is determined by the inductance of the compensation coil and size of the hall sensor.
     • Please see the datasheet snippet that I included above. 

I hope this helps, 

Joe

Dear sir,

Thank you for the guidance!

I now have clarity on the shunt, gain settings, and high-current sensing. I’ve also reviewed the reference schematic for a high-current driver using the OPA454 op-amp, as you  mentioned. Additionally, I analyzed the 100A Closed-Loop Current Sensor design (link:https://www.ti.com/tool/TIPD184), which uses the OPA237 op-amp—a more cost-effective option than the OPA454.

While reviewing the TIPD184 schematic, I observed several connections to the VSS pin (VSS = -30V max). My understanding is that this pin should be at 0V , which has led to some confusion. Could you clarify the correct connection for VSS?

Key observations from the TIPD184 schematic:

1. DRV411 IC: Pins 10, 9, 2, and 3 are connected to VSS.
2. TPS79850QDGNRQ1 Voltage Regulator: Pins 4 and 9 are connected to VSS.
3. Passive Components: C1, C2, R5, and R8 are connected to VSS.
   
   

Your insights on this matter would be highly appreciated.

Hello,

I will provide you with an update tomorrow. 

Thank you for your patience,

Joe