• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 82 subscribers
  • Views 148 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.

TMS320F28075: Using AMC1306M25 for current sampling

Shengyue Zhong
Intellectual 1540 points

Part Number: TMS320F28075
Other Parts Discussed in Thread: AMC1306M25

Hi Team,
 
One of my customer is using the F28075 DSP with the AMC1306M25 for current sensing. The PWM module is used to provide the modulator clock to both the AMC1306M25 and the DSP's SDFM.
My question is: how can I ensure that the SDFM samples data at the center of each data bit, rather than at the edges, in order to avoid capturing switching noise?
 
Specifically, I would like to understand:
  1. How to configure the PWM clock output phase/timing relative to the SDFM sampling window?
  2. Is there a recommended method to synchronize the SDFM sampling point to the center of the modulator output data window?
  3. Are there any reference designs or application notes addressing this synchronization concern for the F28075 + AMC1306M25 combination?
Any guidance or example code would be greatly appreciated.
Thank you!
  • 0
    TI__Genius 9770 points

    This can be done true different techniques like creatring PWM pulses with phase shift.

    To ensure that SDFM samples data precisely at the center of the AMC1306M25 data bit window, you should invert the ePWM clock signal at the microcontroller’s GPIO input level. Because the AMC1306M25 updates its data output (DOUT) on the rising edge of the clock, sampling on the falling edge shifts the sampling point directly to the center of the bit window, maximizing setup and hold margins while bypassing edge-switching noise.

    Set up an ePWM module to generate a symmetric 50% duty cycle clock. then one straightforward and hardware-efficient method to achieve center-of-window sampling is Clock Inversion via the GPIO MUX. You can leverage input inversion. this MCU feature a GPxINV register capable of inverting incoming signals on any GPIO pin before they reach peripheral blocks.

    Best Regards,

    Masoud