• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 226 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS544C20: Standy current

Dicky Malisa Kurniawan
Prodigy 10 points
Part Number: TPS544C20
Other Parts Discussed in Thread: TPS548D22, TPS548B22, TPSM843B22

Hello,

I will not use the PMBUS communication (device configuration/control by the pins and no diagnostic). My product is battery powered. During standby, the CNTL will be set to Low to minimize quiescent current. The only specification about current consumption in the data sheet is:

Ivdd (input operating current) = 10mA (max)

This current is too much. When the device is in off state (CNTL is Low), Is it possible to lower the quiescent current further by cutting the VDD supply using external MOSFET? What is the quiescent current when device VDD is off (not connected to any voltage source) and only VVIN is connected to 15V voltage source.

Please advise.

Thank You.

  • 0
    TI__Guru 56985 points

     

    The TPS544C20 is intended to operate with VIN = VDD, and even adding a MOSFET between them can introduce operational issues when the converter is running due to the high-side current sense using the VDD pin as the voltage for the drain of the high-side FET.  As such, we do not have a characterization of the VIN leakage current for VIN = 15V, VDD = 0V.

    Since you are not using the PMBus interface, I would recommend you consider the TPS548D22 instead of the TPS544C20.  Not only is the TPS548D22 designed to operate with separate PVIN and VDD supply voltages, the VDD = 12V  standby current when switching is disabled is 700μA, which can be further reduced if VDD is lowered below 4V.  The TPS548D22's D-CAP3 control architecture is very similar to the TPS544C20's D-CAP2 + External Integrator architecture, providing high DC accuracy and fast transient response with frequency stabilized adaptive constant on-time Pulse Frequency Modulation control.  Both devices are in the same 40-pin 5mm x 7mm 0.5mm pitch, thermally enhanced QFN package.

    In addition, the TPS548D22 offers a light-load efficiency "Auto-skip" mode that reduces power loss by automatically reducing the switching frequency when the loading current falls below critical conduction (inductor valley current reaches 0A) which can allow the no-load current to approach the standby current while maintaining a regulated output voltage.

    If you don't need the full 30A capability of the TPS544C20, there is also a TPS548B22, rated for 25A that will offer higher efficiency than the TPS544C20 or TPS548D22 at loading currents below about 12A.

  • 0 in reply to Peter James Miller
    Prodigy 10 points

    Hi Peter,

    Thanks a lot for the detailed information. TPS548B22 is not suitable as my product must accept 17V input voltage at the worst case with at least 16A loading. I decided to use TPSM843B22. Although it is pricey but not an issue as the cost is not the main consideration. 

    Please let me know your thought if TPSM843B22 is a suitable choice and if any other points to take into consideration.

  • +1 in reply to Dicky Malisa Kurniawan
    TI__Guru 56985 points

     

    The TPSM843B22 is a good choice with higher integration and a lower shutdown leakage current than the TPS548B22.  It uses fixed frequency advanced current mode control, so it will have higher power consumption at lighter loads than the TPS548B22 when configurated for Autoskip, but I don't know if that is a concern for your application.

    It is worth noting that the TPS848B22 has the same 18V recommended maximum input voltage as the TPSM543B22 does, though TI does recommend using a switch-node snubber to limit the SW peak voltage to 23V when operating above 14V input.  This SW ringing is based on input bypassing and SW layout, which is internal to the TPSM843B22, so we've done the layout for you.