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CCS/TIDM-BIDIR-400-12: current sensing op amp,

Part Number: TIDM-BIDIR-400-12
Other Parts Discussed in Thread: OPA345, OPA365

Tool/software: Code Composer Studio

Hello everyone. 

This question is coming from the thread below. 

I'm dealing with the Current sensing part of the TIDM-BIDIR-400-12 reference design. 

As I explained the thread above, I have still the problem on ADC circuit on design. 

Let me explain one by one. 

In designed(my hardware) circuit, 0.0005ohm shunt resistor exists for the current sensing.  

1. In 10A output current condition, measured with DMM, almost 5mV is measured between two sides of the shunt resistor. 

2. But when I measured the IS_LV- to the ground, showed almost three times the value. (almost 13mV)

3. The offset voltage of the circuit can be measured correctly, and also can be shown correctly in ADC real-time value table in CCS debug mode. 

4. As a result, when I increase the output current by 1A, ADC value feels like I increase 3A. 

5. Furthermore, after the output current reaches 12A, ADC value shown in Real time value table in CCS debug mode went down even if I increase the current. 

At that moment, PIN 3 and PIN4 voltage starts to go far different value(41mV VS 21mV) 

6. I realize the OPA345, op-amp of this circuit is revised by OPA365 in the newer version. I changed the opamp but it didn't change any situation. 

As you recommended last thread, I checked the excel calculation file, and analyze the code with ccs, I think this is not a problem of software or code. 

What can you recommend for this situation? I'm dealing with this problem around 6 weeks, I'm still curious about this matter, and I want to know which part is the problem,