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LM43602: Total quiescent current, including Vbias

TISL
Expert 4640 points
Part Number: LM43602
Other Parts Discussed in Thread: TPS62135, TPS62175, LMR33620

Dear e2e support,

Could you help to clarify one point regarding the quiescent current of our LM43602:

- Operating quiescent current (nonswitching) from VIN: should we add the 85µA (under 3.4V) of the I(BIAS-NONSW), to the 5µA typ (under 12Vin), to get the total power consumption of the chip?

- Operating quiescent current (switching): do we have to add anything to the 27µA typ, to get the total quiescent current of the chip?

If i'm right, the 85µA under 3.4Vbias are equivalent to 24µA under 12V, which is quite important. At the end the total quiescent current in non-switching operation would be higher than the one in switching, so I should miss something here ...

Regards,

  • 0
    TI__Genius 11085 points
    Yes, for non-switching Iq, you should add the 5uA to the 85uA if you don't have external bias source. All these current will come from Vin.

    For switching Iq, 27uA includes everything (bias ties to Vout). No need to add anything.

    When the part operates in closed loop, switching, no load, it is in deep PFM mode, the internal control turns off some of the unused circuitry to further reduce Iq. Non-switching mode is not exactly the same. That's why you cannot just directly compare Iq.

    -Yang
  • 0
    TI__Guru**** 150950 points
    Hi TISL,

    What is your Vin range and application? For example, for most mobile applications, a lower Vin is sufficient and these devices can have much lower Iq. See the TPS62175 and TPS62135 as examples of much smaller and lower Iq devices.
  • 0 in reply to Chris Glaser
    TI__Expert 4640 points
    Hi Yang,
    Thanks for your nice feedback.

    Hi Chris,
    This end application is related to automotive, so 36Vin.
    If any other solution could answer to the high efficiency at light load + low power + low cost, don't hesitate.

    Regards,
  • 0 in reply to TISL
    TI__Genius 11085 points
    The LM43602 is a good choice. You can also consider LMR33620
    www.ti.com/.../LMR33620

    Yang