• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 120 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

TPS54325: The time needs to turn off Vo after EN became low level

Hung Ching Hsu
Expert 3086 points
Part Number: TPS54325

Hi Team, 

My customer is asking following questions. Could you kindly help? Thanks.

1. I think "EN" pin controls output voltage, how long is the time needs to turn off Vo after EN became low level(lower than 0.4V)?

2. Table 2. in p.12 of datasheet have C8+C9(uF), is this a typo of C7+C8(uF)? We can see C7+C8(uF) from figure 4. in p.11.

Regards,

Jo

  • 0
    TI__Mastermind 29640 points

    Hello Jo,

    1. Typically, there is about 200us (Typ) delay from the time the EN is low to the time the switching is off. Then there is time that it takes for the VOUT to fall to 0V, that depends on VOUT, COUT, LOUT and the load conditions.
    2. Yes, that is a typo, C7 and C8 are COUT according to figure 4..

     

    Thanks!

    Tahar

  • 0 in reply to Tahar Allag
    TI__Expert 3086 points

    Hi Tahar, 

    Thank you for the reply!

    Is there any formula that customer can estimate the time needed for VOUT to fall to 0V?

    Tahar Allag said:
    Then there is time that it takes for the VOUT to fall to 0V, that depends on VOUT, COUT, LOUT and the load conditions.

    Thanks.

    Regards,

    Jo

  • +1 in reply to Hung Ching Hsu
    TI__Mastermind 29640 points

    Hello Jo, 

    there is no format per say, but that is typically an RC element  to allow the external COUT to discharge thru resistive load. After the device stops switching, the COUT charge will hold VOUT until the charge in COUT is depleted. If there is a strong resistive load, that will be depleted fast, if the resistive element is not present, then the COUT will take longer to bleed out.  

    thanks 

    Tahar