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Control mode topolgy and output impedance of regulators

Binayak Shrestha88
Expert 1520 points
Other Parts Discussed in Thread: LMZ31520, LMZ31710, LMZ31506, TPS51200, TPS74901, TPS54020, TPS54622

Hi,

For the each of the following six regulators:
(a) LMZ31520
(b) LMZ31710
(c) LMZ31506
(d) TPS51200
(e) TL1963
(f) TPS74901

we need clarity on following two things:

[1] What is the control mode of the regulator
- voltage mode
- current mode (emulated current, average current)
- adaptive constant on time (DCAP, DCAP2, DCAP3, DCAP+)
- DCS control

[2] Where can we get the state space average model? Transient model doesn't help me to get the output impedance curve of the regulator which is a very important parameter for PDN design.

Thanks,

Binayak

  • 0
    TI__Guru 50120 points

    Hi Binayak,

    I am a power module applications engineer so I can only reply for regulators (A,B and C).

    • LMZ31520 ( DCAP)
    • LMZ31710 (Peak Current Mode)
    • LMZ31506 (Peak Current Mode)

    As for the model, there are only transient models (Spice and PSpice) available on the product folder and to the public. I don't think we have the average model available. For the other devices, DDR regulator and LDO, I would recommend making a separate E2E post so that the appropriate engineer can get to your question in a timely manner(usually within 24hrs).

    Regards,

    Jimmy

  • 0
    TI__Mastermind 19891 points

    Hello Binayak,

    Here are some comments on the LMZ devices.

    1. Control Mode

    LMZ31520 = DCAP

    LMZ31710 = current mode

    LMZ31506 = current mode

    2. Unfortunately, I don't believe there is a state space average model for these LMZ devices.

    The list you have spans across several product lines. My colleagues will respond with information on the rest of the devices.

    Cheers,
    Denislav

  • 0 in reply to Jimmy Hua
    Expert 1520 points

    Hi Jimmy and Denislav,

    I have observed  that TI mostly doesn't have state space average models. Is it that they are difficult to extract?

    Does TI have any appnotes that can help us to measure the output impedance of such integrated power modules?

    Thanks, 

    Binayak

  • 0 in reply to Binayak Shrestha88
    TI__Guru 50120 points

    Hi Binayak,

    Sorry for the late reply. Normally TI product folders only have transient models. I am trying to get in contact with the modeling team to see if there are any available average models of this device for public use.

    I found an app note that might help with calculating the output impedance. This would still require an average model of the power module to start the extraction of the data for correlation.

    Regards,

    Jimmy

  • 0 in reply to Jimmy Hua
    Expert 1520 points

    Hi Jimmy,

    Thanks for your effort.

    Kindly do let me know if you find the average models.

    Thanks and regards,

    Binayak

  • 0 in reply to Binayak Shrestha88
    TI__Guru 50120 points

    Hi Binayak,

    You can start with the average model of the internal IC of the power module to get a rough understanding of the output impedance.

    • LMZ31710 ( IC: TPS54020)
    • LMZ31506 ( IC: TPS54622)

    The average model is available on each IC's product folder under "Design & development"

    Regards,

    Jimmy