• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 956 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.

TLV62565: Improving Phase Margin

Martin Seeger
Expert 5411 points
Part Number: TLV62565
Other Parts Discussed in Thread: TLV62585, TLV62569, TLV62568

Dear Team,

our customer would like to use the TLV62565 for following specs:

  • Input: 5V
  • Output: 2.7V
  • Idle output current: 130mA
  • Maximum output current: 511mA

In their initial design, they had a phase margin of 29.65 deg @ maximum load. (Schematics shared via e-mail)

I recommended them to have a look at our application note:

Optimizing Transient Response of Internally Compensated DC-DC Converters (Rev. B) (slva289b.pdf)
http://www.ti.com/litv/pdf/slva289b

and populating a feedforward cap. in the feedback network helped them to increase the phase margin to 39.22 deg.

The data sheet gives the statement, that 45deg should be easy to reach.

Any ideas how to further improve the design?

Thanks a lot and best regards
Martin

  • 0
    TI__Expert 3465 points
    Hello Martin,

    thanks for your interesting question. The procedure explained in the slva289 is the only way to affect the loop gain and phase without touching the output capacitor and inductor. Anyway 40 degrees seems a reasonable number, also taking into account the uncertainty of the measurement and it's method. In general, I would do a final check on the load transient characteristics. If it meets the specification of the customer, I would not worry about getting those 5 degrees more out of the measurement.

    Anyway I would recommend the new generation of products TLV62568 (1A), TLV62569 (2A), TLV62585 (3A) for better performances.