• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 763 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.

MC34063A: Problem with obtaining step-up performance

Pawel Pieta
Prodigy 10 points
Part Number: MC34063A

Hello everyone,

I am working with a MC34063A voltage regulator in order to prototype step-up power management solution, with control logic to switch between three different output values. I encountered some issues while trying to assemble the circuit exactly accordingly to my needs - the output oscillated around 80-110 mA depending on the input setting. I decided to go back to the datasheet and to try build the exemplary step-up configuration in order to better understand what might be the problem while creating my own one.

I built the circuit on a breadboard with the only differences to the datasheet  one (picture below) being: 180uH coil, no Rsc resistor (no current sense, pins 7 and 8 connected together). When the input is set on 12V, the output measured is 10.96V. When increasing the input, the output increases accordingly, always staying around one volt below the input value.

Any advices what may be the reason for this kind of performance instead of obtaining the expected v_out value of 28V?
Thanks in advance.

  • 0
    TI__Mastermind 21720 points

    Hi Pawel

    Thanks for reaching out with your question and for considering the MC34063A in your design.

    I have a few questions that should help debug the issue. 

    1. Can you please provide the schematic?

    2. What are the applications specifications? (VIN Range, VOUT, IOUT, Fsw)

    3. Was your original circuit built on  a bread board? This is not recommended as switch mode power supplies are inherently noisy.

    Thanks,

    Garrett