• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 38 subscribers
  • Views 645 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.

TPS63031 Efficiency Comparison with SwitcherPro Results

Charles McCarthy
Intellectual 510 points

Other Parts Discussed in Thread: TPS63031

Hello!  I am trying to design a boost converter with inputs of about 3.0V and an output of 3.3V, with 100mA of current (max).  I was looking at the TPS63031 as the efficiency numbers looked pretty good. From the datasheet (SLVS696A) Figures 11 and 12, it looks like with a 3.0V input I should see an efficiency of 89% - 85% from the graphs with 100mA output.

However, when I run the device in the on-line version of the SwitcherPro tool with an input range of 2.9V to 3.1V, and an output of 3.3V @ 100mA max, it gives me an efficiency curve way down in the dirt - about 60%.  I ran the tool letting it determine the best component values.  I noticed the note at the bottom of the efficiency graph:

"Duty cycle is too low for the device in this situation. Calculated on time is below the 'Minimum Controllable On Time'of the device! Use the analysis tab to view the calculated on time. This device has a 'Minimum Controllable On Time' of 160ns."

It appears that the device has very few "knobs" to make adjustments.  I tried changing the capacitors and inductor but none of these changes resulted in a reasonable graph.  Any ideas on what's going on here?

Thanks!

Charles

 

  • 0
    TI__Mastermind 36110 points

    Please repost your question to the TI E2E Community/Support/Other Analog/Analog eLab and Tools forum

  • 0 in reply to Matthew Day
    TI__Mastermind 36110 points

    The error msg in SwitcherPro about 'minimum ontime' is incorrect.  This IC works well in your application.  This will be corrected. 

    As specified in the message below schematic, SwitcherPro does not model efficiency in PFM mode.  The data should be reasonable accurate in PWM mode. 

    I do not suggest modifying the external components from the recommended values.  These components must remain very close to the recommended components to ensure proper performance and stability.  The recommended components in the EVM provide very good performance.  To understand actual performance, I suggest you purchase the EVM.