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TPS62864: I_Q and I_SD

Ella KIM
Expert 4212 points
Part Number: TPS62864

Tool/software:

Hello Team,

Can you please clarify what Iq exactly indicates? What is the occasion that the device is enabled by EN = high but not switching?

Eventually, I'm wondering how much of current is consumed in stand-by mode vs. active mode. 

- stand-by mode : VIN is applied with EN = low

- active mode : VIN is applied with EN = high, Vout is being regulated.

Per datasheet, it seems I_SD shutdown current indicates stand-by mode.

What about active mode? It may depends on operating condition. Can you please provide feedback considering my target application is 4Vin 1.2Vout 2Aout? 

Many thanks,

Ella

  • 0
    TI__Expert 4212 points

    Hi Team, 

    Any feedback? More specifically, I'd like to know current consumption during no load (device is switching).

  • 0 in reply to Ella KIM
    TI__Expert 4478 points

    Hi Ella,

    Iq is the active mode current. Device not switching indicates, that no current is drawn at the output, so is only the device internal current consumption without switching losses.

    Regards, Werner

  • 0 in reply to Werner Lummer
    TI__Expert 4212 points

    Hi Werner,

    Can you please let me know current consumption with switching but without load? That is the item of interest for customer to estimate total current consumption of their system.

  • 0 in reply to Ella KIM
    TI__Expert 4478 points

    Hi Ella,

    to my knowledge, this value is not available. The device is only switching with load. Switching without load would raise the output voltage. I will check with an colleague later today to confirm this.

    Regards, Werner

  • 0 in reply to Werner Lummer
    TI__Expert 4212 points

    Hi Werner,

    When there's no load, I believe the device will operate in Power Save Mode and consume the minimum current while switching as described in datasheet. Even though it is not a specific test data, it would be helpful if you can provide rough number (several mA or hundreds of mA etc.).

  • 0 in reply to Ella KIM
    TI__Expert 4478 points

    Hi Ella,

    We do not have the exact number you are asking for this device. I checked with other devices and the so called 'no load input current' that includes switching at no load was x1.2 to x1.5 of the listed Iq. So you can expect something below double the Iq in the datasheet.

    Please note that this is depending on the exact application, as all kinds of parasitics will influence this number.

    Since Iq is 4μA and you are asking whether it is mA or hundreds of mA, I would answer with <1mA.

    If you need the input current at a specific load, you may take a look at the efficiency graph in the datasheet.

    Further details can be found in these two app notes: slyt412.pdf and slyt558.pdf

    Regards, Werner