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TMCS1126: Can TMCS1126 voltage output can Directly go to my STM32 3.3V ADC microcontroller pin ?

kalana de silva
Prodigy 140 points

Part Number: TMCS1126

Tool/software:

Hi, 
I am using the TMCS1126 in my dual active bridge to measure the current and that will be used in current control loop. 
I am using the STM32 3.3V ADC pin at the MCU. 

1. Can i use the Vout from TMCS1126 go straight to the ADC pin or I need a differential amplifier ? 
2. How to use Vref and OC ? Example would be great. 


Thank you

  • 0
    TI__Expert 6425 points

    Hi Kalana,

    I will assume you are using a 3.3V supply for the TMCS1126, but if you are using a 5V supply you will need to account for that when trying to feed a 5V output to a 3.3V input.

    If you are using this in a bidirectional application then you need to measure your output voltage with respect to the reference in order to determine the direction of current flow. If your ADC has a reference input you can feed Vref to that reference input, otherwise, you can use a difference amplifier.

    Section 8.3.7 of the DS provides details about how to configure and use the OC pin. I would refer to that and if you need any clarification please let me know.

    The Vref is dependent on which version of the device you are using (see below). The reference is used to enable bidirectional current sensing. If your voltage output is less than the reference voltage that means your current is flowing in the negative direction. 

    Best,

    Holly

  • 0 in reply to Holly R
    Prodigy 140 points

    Hi Holly, 
    I will be using my 3V3 to power the current sensor and this is the same 3V3 used to power the MCU (they reference the same GND). The data sheet does not clarify if I need a differential amplifier before the ADC pin in the MCU. 
    Can you please confirm if this can be sent directly to the ADC since the Vs voltage is 3.3V and the reference GND are same ? 

  • +1 in reply to kalana de silva
    TI__Expert 6425 points

    Hi Kalana,

    If you want a differential measurement then yes you need to go through a diff amp before feeding to the MCU, but if you are using a single ended measurement then you can feed VOUT directly to the MCU input.

    Best,

    Holly