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Original question:

DRV8703-Q1: how to apply PWM signal

DRV8703-Q1: why we need these two modes

Elec Cheng
Expert 7055 points
Part Number: DRV8703-Q1

Hi Expert,

As you can below, when setting MODE= 0, I can use a GPIO on IN1/PH to control direction and use PWM on IN2/EN to control speed. When setting MODE= Hi-Z, I may need to use two PWM signals. Though, I still don't get why we design these two mode because I think they are very similar. Could you please share why we design as this? Thanks.

BR,

Elec Cheng

  • 0
    TI__Expert 4970 points

    Hello Elec,

    I am happy to address your question. In short it is because it is an industry standard, and all 3 modes are widely used. By innately having an independent half bridge control as one of the control modes it allows us to be a direct replacement to other sockets that are in the market. Additionally, by having complete control of the H bridges, we can choose which slow decay we want, whether it is high side slow decay or low side slow decay. 


    As a matter of fact, I actually created a video that compares and contrasts the advantages of different control interfaces. You can find more about it here: 

    https://www.youtube.com/watch?v=up5edFaToq4&t=6s

    Best,

    Pedro Arango Ramirez

  • 0 in reply to Pedro Arango Ramirez
    TI__Expert 7055 points

    Hi Pedro,

    I watch the video and it is helpful. The main difference is GPIO + PWM and PWM+PWM. But I still don't get that is there such big difference between one GPIO and PMW? I mean I can also operate GPIO as PWM out as long as the interface supports this kind of usage. May you help clarify more? Thanks.

    BR,

    Elec Cheng

  • 0 in reply to Elec Cheng
    TI__Expert 4970 points

    Hello Elec,

    You are absolutely correct. There really is not much different, if you have a GPIO you could run it as a PWM if the interface supports that kind of usage. In a lot of cases the hardware in the microcontroller is capable of providing both. However, the main reason that we provide both, is that some of our customers already have code, protocols, or design considerations in mind with a particular control interface. If we are able to offer all 3 it allows us to be able to fit easier in the system's sockets as in some cases we are a pin to pin replacement that responds similarly to the software that has already been written.