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TPS62051 Quiescent Current

Other Parts Discussed in Thread: TPS62051, DAC5674

The datasheet lists the quiescent current of the TPS62051 as 5uA, and does not specify whether this is low power or low noise (forced PWM) mode. I have a feeling it is for the low power mode, but I would like confirmation.

I will be driving the SYNC pin high, forcing it into constant-frequency operation, and I would like to know the typical quiescent current for this part in this mode.

Thank you.

  • Hi,

    The test conditions are EN = VI, LBI = GND.
    In this condition the voltage at LBI is less than the LBI trip point and all other internal circuits are shut down, reducing the supply current to 5 µA.
    Therefore it is independent of the Sync pin.
    This is described in chapter 9.3.3 in the DS.

    Regards,
    Michael
  • Michael,
    Thank you for the quick reply.
    With regard to my second question, is there any information for this part when it is in operation? Specifically, I would like to know what the quiescent current is when LBI = VI, EN = VI, and SYNC = VI, with some nonzero output current. I'm a little confused why this isn't already in the datasheet, to be honest.

    Thank you.
  • Hi,

    The Iq is defined in a non switching condition. Please have a look in following paper for more information: www.ti.com/.../slyt412.pdf

    Could you share more details of your application? What are your concerns?

    Regards,
    Michael
  • Ah, then this is an issue of me not understanding what to look for in a part.

    My application is USB2.0 powered and very noise sensitive, so I am trying to figure out what the best option(s) is/are to drop 5V to 3.7. I was assuming Iq was the total lost current of the device, but now I understand I was incorrect.

    What would be the method of determining how much power is lost in a switching regulator? It has something to do with efficiency, I'm sure, but exactly how I'm not clear on. Maybe Vout x Iout x Efficiency?

    I appreciate all your help.
  • What exactly is noise sensitive in your application? What is your maximum load current?

    Yes, Vin x Iin - Vout x Iout is the power you will loose. Efficiency = Vout x Iout / Vin x Iin .

    Regards,
    Michael
  • This power line includes a DAC5674 which is our most noise sensitive part. The load on this will max out around 500mA, so using the 62051 will give some headroom. There are a few other parts I'm considering as well, all capable of outputting >600mA. Though, I chose them in part based on Iq, which is something I don't really care about - this switcher will always be on. I suppose I need to just look at efficiency for power loss, and use a device in fixed-frequency mode to more easily filter out that noise.

    Sorry this is pretty basic stuff, this is the first time I've really had to dig in to find the best parts for an application.
  • Yes you can check on the efficiency graphs in the DS.
    There are also newer and smaller parts which could fit for your application like the TPS6213x family.

    Regards,
    Michael
  • Michael,

    I suppose that part would technically work, but it's only barely more efficient, basically the same size, and doesn't give me the option to force it into PWM mode - something I'd like to be able to do to more easily filter out the switching noise.

    Thanks for your help, it looks like the TPS62051 will be our tool of choice for this application.