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TPS6306X: Power consumption without load.

Oscar Gomez Fuente
Expert 2066 points


Hi,

I'm working on the design of a portable device. I'm very concerned about the power consumption.

In one hand, I would like to know the power consumption without load. According to the datasheet The máximum Iq (Input voltaje quiescent current) [Iout=0 mA, Ven=Vin=5V, Vout=5V] is 60uA:

So, Is the máximum power consumption going to be 60uA without load?

And in the other hand, How is the power consumption if I enable the PS/SYNC pin (enalbe power save mode)?

Best regards.

  • 0
    TI__Guru 57737 points

    Hi ,

    Unless otherwise noted in the datasheet for a part, IQ is defined as the current drawn by the IC in a no-load and nonswitching but enabled condition. “No load” means that no current leaves the IC to the output. Typically, this would be current leaving via the SW pin on buck converters or via the VOUT pin on boost converters. All of the IQ simply travels inside the IC to ground.

     “Nonswitching” means that no power switch in the IC is on (closed). This includes the main or control switch as well as the synchronous rectifier if both are integrated into the IC. In other words, the IC is in a high-impedance condition with a power stage that is completely disconnected from the output (except for integrated MOSFET body diodes on some devices that cannot be turned off). “Enabled” means that the IC is turned on via its EN pin and is not in a UVLO or other shutdown condition. IQ measures operating current, not shutdown current, so the device must be on.

    Lastly, IQ is meaningful only in power-save mode, so if this mode is an option for the particular device, it must be enabled. If the device runs in pulse-width-modulation (PWM) mode, then the input current to the power stage and switching losses more than dwarfs the miniscule amount of current, the IQ, required to run the device.

    For more information on Quiscent Current please refer the application note below,

    http://www.ti.com/lit/an/slyt412/slyt412.pdf

    Hope this answers your question.

    Regards,

    Praveen GD

  • 0
    TI__Guru**** 151080 points
    Yes, the app note in the other reply is worth a good read. It should point out that you never have a truly no-load condition. There is always leakage from your load (even if it is off), pull-up/down resistors, and the FB resistors which consume some uA on the output. You can order the EVM and test the circuit under any condition you want.

    We measured the no-load input current on the EVM with these results:

    Vin = 3V
    Iin = 81.06uA

    Vin = 5V
    Iin = 59.55uA

    Vin = 9V
    Iin = 61.05uA

    What Vin, Vout, and Iout do you need?
  • 0 in reply to Chris Glaser
    Expert 2066 points
    I add the link of this helpful thread: e2e.ti.com/.../1778840

    Best regards.