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Which Component to use for PWM based Isolator Prototype

Ahmed Amer
Prodigy 30 points
Other Parts Discussed in Thread: ISO6741, ISO7741

Hi, I want to create a prototype of the isolator based on PWM for my customer based on the "Designing with digital Isolator Guide" document. Can you suggest components to do the PWM modulation part (which is shown in the figure from the guide), knowing that the modulation part will be done with a PCB?
 
Thanks in advance,
Ahmed

  • 0
    TI__Genius 17100 points

    Hi Ahmed,

    Thank you for posting, and welcome to E2E!

    TI digital isolators already have the different circuit blocks shown in Figure 1 and Figure 2 of "Designing with digital isolators (SLYT335)" integrated, so there is no need for a PWM modulator or other external discrete components for isolation. Our digital isolators need simply to be configured with power supplies and signal connections as shown in the example circuit below:



    Although the internal architecture of our newer isolators is different from the technology described in "Designing with digital isolators," we recommend our new devices for your customer's designs, such as ISO6741 or ISO7741. These parts are more robust, have higher isolation ratings, and are available in multiple channel count and configuration options.

    Please let us know if there is any additional information we can help with.


    Thank you,
    Manuel Chavez

  • 0 in reply to Manuel Chavez
    Prodigy 30 points

    Hello Chavez,
    thanks for your quick response.  

    The customer wants to create his own "PWM-based simple isolator", so I followed along with "Designing with digital isolators guide" which needs to include a PWM modulation. So basically a PWM modulator will be needed and I can not figure out how to realize it on a PCB. I told him before that we could buy any of the in-market isolators but that is not what he wants.

    Thank you,
    Ahmed

  • +1 in reply to Ahmed Amer
    TI__Genius 17100 points

    Hi Ahmed,

    You're welcome!

    Most MCUs can generate PWM signals, and a discrete PWM generator can be created using TI components by following the design in this reference circuit (SBOA212A) and this Reference design (TIPD108). This circuit generates a 500kHz PWM waveform with a duty cycle that is inversely proportional to the input voltage.

    Please encourage your customer to consider using TI digital isolators, especially since there are many benefits to doing so. We do not provide support for designs without TI components. 

    Let us know if there are any additional questions regarding TI's isolation devices. For support regarding the PWM components or other TI devices, a new thread can be created using the red and yellow buttons in the upper right corner of this window.


    Thank you,
    Manuel Chavez