• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 81 subscribers
  • Views 180 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

TMS320F280045: How many DC-DC converters are controlled by a single TMS320F280045 ?

Hideaki Nambu
Mastermind 9125 points
Part Number: TMS320F280045

Hello,

Could you please advise ?

My customer asked me how many DC-DC converters are controlled by a single TMS320F280045.

 

The spec of the DC-DC converter:

  • Single switch per converter channel. Just the main switch. No rectifier switch.
  • fSW = 50kHz.
  • Two ADC inputs per converter.

 

(Background)

My customer would like to operate multiple converters in parallel.

Especially I would ask your advice about the limitation comes from PWM ch, ADC input ch, and CPU execution time.

  • PWM ch - 16 HRPWM terminals.
  • ADC input ch - 21. Two inputs per converter, so maximum ten converters.
  • CPU execution time - I would ask your advice.

 

(CPU execution time)

I'm trying to understand the C2000 Digital Control Library Version 3.2 User’s Guide,

http://dev.ti.com/tirex/explore/node?node=AH4e9SC7P9whvmewbFSmVA__5C6SEVO__LATEST

In the page-7, the CPU cycle time is listed. It would be necessary to select several function to have a total processing time for ADC, PWM and PID. But the point is difficult for me.

 

 

  • 0
    TI__Genius 10995 points

    Each forward converter will need to run a PID controller or a 2 pole 2 zero (2p2z) controller for voltage regulation. For each of these controller you will need about 100 cycles of TMS320F280045 for ADC read, control calculation and PWM duty update. That means the time for one controller is about 100*10nS = 1uSec.

    Now if the PWM frequency and the Sampling frequency are both 50kHz then you have total 20uSec time to do all calculations.  This means theoretically you can have 20 PID/2p2z controllers running in a single 100MHz F280045 MCU when the sampling frequency is 50kHz.

    Therefore, you can control 20 Forward converters with single F280045. However you might be limited by PWM and ADC resources.

    Shamim