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F28069M BOOSTXL-BUCKCONV - How to implement current mode control

Andrea Pastore
Prodigy 30 points
Other Parts Discussed in Thread: LAUNCHXL-F28069M, BOOSTXL-BUCKCONV, POWERSUITE, CONTROLSUITE, TMS320F28035

Hi,

this is my first post on this forum. I searched some older posts related to what I'm doing but I didn't find anything.

I'm working with the LAUNCHXL-F28069M (http://www.ti.com/tool/LAUNCHXL-F28069M#0) and with the BOOSTXL-BUCKCONV (http://www.ti.com/tool/boostxl-buckconv), using the PowerSUITE software (https://e2e.ti.com/blogs_/b/toolsinsider/archive/2015/03/16/digital-power-boosterpack-and-powersuite-software-tools-give-developers-the-power-to-innovate).

I have already tested the example project given by ControlSUITE software (C:\ti\controlSUITE\development_kits\BOOSTXL_BUCKCONV\v1_01_00_00\Buck_VMC_F28069M) and it works properly (both open loop and closed voltage mode loop).

Now I'm looking for current mode implementation exploiting the same example project: I would like to modify the C code in order to add the current loop control by measuring in Real-Time the current value (not the average current value).

My idea is to use the open-loop mode adding a section containing the real time current loop, in order to drive the PWM directly. The goal is to open the buck SW when the current reaches the peak value (depending on Vout), and to close the buck SW at the end of each switching period. How can I do it?

I'm not a computer engineer. This is the first time I work with a TI board and with TI libraries, so I'm not very confident. Please give me some hints.

Thank you,

AP.

  • 0
    TI__Genius 10820 points

    Hi Andrea,

    Current mode control of a buck converter is implemented on the C2000 DPS workshop kit. This kit uses TMS320F28035 device, which is from the same family of microcontrollers as F28069. The hardware, software and documentation files for this kit can be found on the wiki page here: http://processors.wiki.ti.com/index.php/C2000_DPSWorkshop

    I hope this helps.

    - Hrishi

  • 0 in reply to Hrishi Nene
    Prodigy 30 points

    Thank you for the answer.

    Now my question is: can I implement peak current control using my board BOOSTXL-BUCKCONV (with F28069M)? If yes, how can I implement it? Should I write all the C (or assembly) code?

    Thank you, 

    AP

  • 0 in reply to Andrea Pastore
    TI__Genius 10820 points

    Andrea,

    Implementing peak current control on BOOSTXL-BUCKCONV using F28069 launchpad is not straight-forward. You may instead use F28377S launchpad to do this. You can use the DPS workshop code as a starting point to develop this code. If you are set on using the F28069 device for your application, then I would suggest acquiring and/or reviewing the DPS workshop material for the current mode control implementation on that board with the F28035 device (a sub-set device of 28069). 

    BOOSTXL-BUCKCONV expects both high side and low side PWM drive signals from the controller. The delayed trip mechanism on the F2837x (and F2807x) PWMs (not present on the F28069 PWMs) can be used to generate correct PWM waveforms for both high-side and low-side switches of the synchronous buck. Without this mechanism, significant software overhead may be required to generate correct PWM waveforms. The DPS workshop kit relies on the external FET driver to generate the complementary high side signal allowing the use of F28035/F28069 devices without additional software overhead.

    Hrishi 

  • 0 in reply to Hrishi Nene
    Prodigy 30 points

    Thank you very much Hrishi! These are informations that I need.

    AP