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INA220 / Trigger mode operation , Current LSB, I2C Write/Read time

Ryuji
Guru 20090 points

Other Parts Discussed in Thread: INA220

Hello,

Could you please kindly let me know about INA220 ?


(1) Trigger mode operation
INA220 has two mode of Continuous mode and Triggered mode.
I understood that Continuous mode is always sense BUS and Shunt mode by the registered conversion time.

About the trigger mode, I can't find any detail operation in the datasheet.
Could you please kindly let me know the detail of trigger mode ?


(2)Current LSB
How many value of LSB when Host CPU read current LSB ?

(3)time between Write/Read registers
Could you please kindly let me know below time ?

-between "Configuration Write"- "Calibration Write"
-between "Calibration Write" - "CURRENT Read"
-between "Current Read" - "BUS Read"

Is below time correct ?

t(SUSTO) + t(BUF) + t(HDSTA) = 600 + 100 + 100 = 800ns


Best Reagards,
Ryuji Asaka

  • 0
    TI__Expert 6930 points

    Hi Ryuji,

    Thank you for your questions regarding the INA220.

    1) Trigger Mode Operation:

    There are 3 different trigger modes of operation.  Shunt only, Bus only or Shunt and Bus.  The triggered conversion(s) starts following writing into any of these three trigger modes in the configuration register.  please refer to Table 6 in the data sheet for the configuraion register settings to enter one of the trigger modes.  The conversion times for the triggered conversion(s) is determined by the SADC and BADC settings also in teh configuration register.  Table 5 describes the conversion time options.  The CNVR bit of the Bus Voltage Register can be used to determine when the triggered conversion(s) are ready to be read.  To perform the next triggered conversion please repeat the above steps starting with writing to one of the triggerd modes in the configuration register.

    2) Current LSB:  I do not understand the question you are asking...can you please clarify your question?

    3)Timing:

    -between "Configuration Write"- "Calibration Write" = TBUF; Fast Mode = 600nS, High Speed Mode = 160nS


    -between "Calibration Write" - "CURRENT Read" = TBUF; Fast Mode = 600nS, High Speed Mode = 160nS

    -between "Current Read" - "BUS Read" = TBUF; Fast Mode = 600nS, High Speed Mode = 160nS

  • 0 in reply to Edward Mullins
    Guru 20090 points

    Hello Edward san,

    Thank you for the reply.
     
    (1)
    Thank you.
    I understood that  conversion is started when we write Configuration Register as trigger mode.
     
    (2)
    Sorry.
    We can set current LSB arbitrarily in the range of FSR by calibration register .
    Is my understanding correct ?
     
    (3)
    Thank you.
    I understood that  we need TBUF time.
     
    Best Regards,
    Ryuji Asaka
     
     
     
     
  • 0 in reply to Ryuji
    TI__Expert 6930 points

    Hi Ryuji,

    Yes on number 2 your understanding is correct.