• State Resolved
  • Locked Locked
  • Replies 7 replies
  • Subscribers 64 subscribers
  • Views 403 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.

TPS53319: About Current Sense, Overcurrent and Short Circuit Protection

Tsukui Yusuke
Guru 21930 points
Part Number: TPS53319
Other Parts Discussed in Thread: TPS53515, TPS548A20

Hi,

Could you tell me about TPS53319 OCP?
The following contents are described in the data sheet.



In case of “Duty> 45%” condition,
How much is the OCP accuracy degraded?


Customers are trying to use the TPS53319 under the following conditions.
Vin=5V, Vout=2.6V, (Duty:52%)

I announced the OCP issue to the customer based on the datasheet.
However, it is necessary to have information on how much the OCP accuracy will be reduced in order to correct the circuit.
Could you give me your advice?

Regards,
Yusuke



  • 0
    TI__Genius 14455 points

    Hi Yusuke-san,

          We are looking into this and will get back to you.

    regards,

    Gerold

  • 0 in reply to Gerold Dhanabalan - Online Design Tools
    Guru 21930 points

    Hi Gerold-san,

    Thank you for your support.
    Please contact me again once you have some updates.

    Regards,
    Yusuke

  • 0 in reply to Tsukui Yusuke
    Guru 21930 points

    Hi Gerold-san,

    Is there any updates about  this issue?
    Please contact me again once you have some updates.

    Regards,
    Yusuke

  • 0 in reply to Tsukui Yusuke
    TI__Genius 14455 points

    Hi Yusuke-san,

         With higher duty cycles, the device can appear to be hitting current limit at lower currents. It is recommended to stay lower than the 45% duty cycle as mentioned in the datasheet.

    However, if the Vinmax is 5V, why pick the TPS53319? We have alternate devices that could suit your needs. Can you please let me know your Iout requirement and also other design requirements and we can suggest a more suitable part.

    You can try using WEBENCH as well to help with your part selection webench.ti.com/power-designer

    Regards,

    Gerold

  • 0 in reply to Gerold Dhanabalan - Online Design Tools
    Guru 21930 points

    Hi Gerold-san,

    Thank you for your response and support.
    As the background of this question, Customers are designing circuits using Intel CRB(Customer Reference Board) as a reference.
    Intel CRB uses TPS53319 as DDR power supply (Input voltage is 5V.).
    Therefore, In order to change the design, customer needs to know the current limit accuracy degradation information in detail.

    If this contains confidential contents, is it possible to send my direct E-mail address?
    E-mail Address : tsukui-y@macnica.co.jp

    Regards,
    Yusuke


  • 0 in reply to Tsukui Yusuke
    TI__Guru 56965 points

     

    It is not that this contains confidential contents, rather that the drop in OVP threshold has not been characterized full for duty cycles larger than 45%.  After reviewing the root cause of the issue with the design team, there is likely little impact at 52% duty cycle, but the OC level will decrease as the OFF time decreases, dropping to approximately 1/3 of the programmed level at 85% duty cycle.

    Since the root cause of the issue is related to the low-side FET on-time, and the recovery of the switch-node sensing comparator after the turn-on of the low-side FET lower switching frequencies will be less likely to see much impact.

  • 0
    TI__Guru 56965 points

     

    I would strongly recommend the customer consider using the TPS53515 or TPS548A20 device rather than the TPS53319 for a 5V to 2.6V output.  These devices use a more updated version of the D-CAP mode control used by the TPS53319 and do not have the OCP tolerance implications that the TPS53319 has with higher duty cycles.  While it is unlikely that there is a significant shift in the OCP threshold between 45% duty cycle and 52% duty cycle, using the TPS53319 converter in a 5V to 2.6V could result in a current limit threshold that is heavily dependent on the VIN voltage and changes significantly as the 5V input voltage decreases over expected system tolerances. 

    It would take some time to test a large enough sample of TPS53319 devices over temperature and worst-case design conditions: Minimum Vin, Maximum Switching Frequency, process and production to provide a confident answer on how much the current limit could be reduced in the customer's application.

    In addition, these newer devices offer smaller size and improved performance for a better overall solution.