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Digital control for buck DC-DC

Maher Al-greer
Intellectual 275 points
Other Parts Discussed in Thread: UCD7230, TMS320F28335, PTD08A020W, UCD7242, UCD7231

Hi,

I want to investigate an adaption method for dc-dc converter but the design of dc-dc buck converter i designed is not good enough, in terms of noise and the interface with the DSP is not good I guess. So I need to find synchronise buck dc-dc converter development board that working with rang of 20-40 kHz and this board can connected to DSP F28335. I mean the DSP is the controller of the converter, actually I had a look to the data sheet of  UCD7230 but I don’t know if it is working with low frequency, and I don’t know if I can connected to the F28335.  

So, please if anyone can help me with this issue?

Regards

 

  

 

  • 0
    TI__Intellectual 1755 points

    Maher,
    There is a wide range of evaluation boards and reference designs for the C2000 MCU family.  This page has a good summary of the various platforms. 

    The UCD7230 is a good choice for driving a synchronous buck regulator at these low frequencies.  Of course the TMS320F28335 has enough MIPS and a high enough resolution on the PWM output that you could run the switcher almost 50X faster--thereby using a 50X smaller inductor and substantially less input and output capacitance.  If you decide to explore a faster switching frequency, I would recommend the UCD7231 which is an enhancement to the UCD7230 that supports narrower pulse widths.  Or, if your current requirement are <10A, you could consider the UCD7242 which has imbedded power MOSFETs.  Or finally, you could consider one of the PTD power modules such as the PTD08A020W.  This module packages the UCD7230, MOSFETs, inductor, input and output capacitance on an engineered and tested daughter card.  (What you are buying with a module is a known good version of the tricky layout of caps and grounding around the MOSFETs.) 

    I hope that this helps.
    Mark

  • 0 in reply to Mark Hagen
    Intellectual 275 points

    Hi,

    Thank you very much Mark for your concern,

    Sorry but the link of the page that you mention it in your reply is not open with me.  I would like to ask you, is there any model of PTD08A020W  or UCD7230 ready to buy it directly and can connected directly as well to my DSP or I need to buy the chip and design the PCB for it. Also, I would like to ask about the values of inductance and capacitance in the existing board is working with low switching frequency, because actually I calculate the values of L and C depend on switching frequency of the circuit and Mix. current. However my current Mix is 2A.

     

    Best Regards

     

        

  • 0 in reply to Maher Al-greer
    TI__Intellectual 1755 points

    Maher,
    Sorry about the link.  The post above is now corrected. 

     

  • 0 in reply to Mark Hagen
    Intellectual 275 points

    Hi,

    Thank you it is working now,

    But I am not looking to this development board of DSP with dc-dc converter, because I am already have a ezDSP 28335, I need only  a separate  board of buck dc-dc converter like PTD08A020W. Please can you answer my last reply about the working of PTD08A020W with low frequency range from 20-40k Hz because I was looking to data sheet I saw the Min. frequency is 300kHz. Actually I need to buy this board of dc-dc converter as soon possible so your answer will help me to decide which board is suitable to my application.

    Best Regards

     

     

  • 0 in reply to Maher Al-greer
    TI__Genius 13700 points

    This forum may not be the best choice for your questions.

    Digital Power relates to the loop control operation of the PWM controller being digital vs. the more traditional analog loop control methods.

    It sounds like you are looking for a complete DC/DC module solution, which operates with a 20-40KHz switching frequency, that you can plug in to your DSP board.

    You may want to repost in the power modules section, http://e2e.ti.com/support/power_management/powermodules/default.aspx

    You may have a difficult time finding any new module based designs that run this low in frequency, most system designers are trying to minimize the space occupied by the power so that they have more space for there system components, as such, frequencies have been climbing into the hundreds of KHz and even into the low MHZ.

    There are still PWM controllers which will operate down into this range but you may need to design your own DC/DC converter .

    Regards