INA236: INA236

Hi Ku, 

There are a few factors to consider. Firstly, the full scale range of the differential input on the INA236 is 81.92mV. The offset voltage of the AMC1200 on the input would be 1.5mV (max), however this would multiply by 8 as the AMC1200 has a gain of 8, so it would be 12mV. This would already account for ~14% error and wouldn't be very reliable. I also have a few questions: 

• What differential input voltage will be fed into the AMC1200? 
• What voltage are you trying to measure?

Another factor to consider would be to ensure you are not exceeding the differential shunt range of the INA236, it would be easy to exceed this as the AMC1200 already amplifies the signal by 8, but this would depend on the differential input voltage you decide to use. The AMC1200 already outputs a voltage to measure, what is the purpose of measuring that voltage with the INA236? Please let me know if you have any questions. 

Hi Hamida,

Actually i trying to measure the DC voltage input of my circuit which the power input range is 40Vdc to 160Vdc.

I use AMC1200 to get the voltage measurement and thought of use INA236 ic to get the output reading of AMC1200 data.

My AMC1200 differential output full scale range is around 2V when my input is 160Vdc.

  what is the purpose of measuring that voltage with the INA236?

-Because of the I2C/SMBus-compatible interface. 

So,i can't use INA236 to read my AMC1200 differential output because the value already exceed INA236 differential input range 81.92mV.

What the different of this differential (Vin+) - (Vin-) with the differential input range 81.92mV?

Thank you.

Best regards,

Ku

Hi Mohamed,

Now i modify my design and plan to use INA236 device to do current sensing.

I want to monitor the current in my BUS voltage Vdc=12V, max current 2A. Rshunt =10m Ohm

Is my design for current sensing correct ?

SCH-1096-00 Current Sensing INA236.pdf

Hi Lee, 

The design seems fine. However, the RShunt you're using may be problematic as it doesn't seem to be using the full resolution. You may use the following tool to choose the correct shunt resistor that fits within your specification: https://www.ti.com/lit/an/sboa511a/sboa511a.pdf?ts=1701991855092. If you have any questions, please feel free to let me know. 

Hi Mohamed,

Based on the application note and INA 236 specification, i had make the below modification to my design,

Bus supply rail (Vcm) = 12V , Average current = 0.8A, MAx monitor current,Imax = 1.5A, ADC range selection ,Vsense max =+/- 81.92mV.

-Rshunt < Vsense max / Imax, =81.92mV / 1.5A =54.61m Ohm. so final Rshunt use is 50m Ohm.

-Current_LSB(min) =1.5A/ 2*15 = 45.77637uA. I choose 100uA

-Shunt_calibration =0.00512 / (100uA x 50mOhm) = 1024

-current  = Current_LSB x current value read from register =100uA x current value.

Please give your comment whether above design and setting will work?

Thank you

Best regards,

Ku

SCH-1096-00 Current Sensing INA236_A.pdf

Now i have the INA236EVM on hand, can i use to evaluate the EVM without the SCB board through the GUI?

May i know TI got any sysConfig tool which can help me generate configuration code for INA236.

I use linux firmware & IPC for my device.

Thank you .

Best regards,

Ku

Hi Mohamed. Can I know what to with the SysConfg file? The mcu_msWait function is empty

How do we compile the sysconfig and do we load to the hardware for testing?

Hi Mohamed,

I'm using industrial PC I2C protocol to communicate with TI device.So how should i make use of this SysConfig file?

Do i need some driver or can you give me some example?

Thank you.

Best regards,

Ku

Hi Mohamed,

Now i use Arduino IDE to test the INA236EVM. 

Do TI have any Arduino library of INA236 which i can use to test the current sensor?

How can i add those INA236 sysConf file into my Arduino library so that can use it for current sensing?

I got found a Arduino library INA2XX-1.1.0 from GitHub. Can this library use for INA236?

Thank you.

Best regards,

Ku

INA2xx-1.1.0.zip