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Debugging Schematics

Part Number: DRV8353
Other Parts Discussed in Thread: TIDA-00364, TIDA-00774,

Tool/software:

Hi,

Since I am a sophomore student in college, I had no experience in power electronics. But still I have prepared some schematics using many documents and reference designs, now I want to start with designing PCB of my motor driver. Is it possible to check and debug my schematics to ensure it is a proper driver circuit. You can find attached document of my schematics.

Thanks for your attention, hope you can help in sudden since I have very small time until the deadline,

Mert

Koç University

PS: I have used TIDA-00774, TIDA-0010056, TIDA-00364 reference designs for my circuits with many additional instructive materials TI provided. But I am curious why in the reference design TIDA-00774, IA_IDC is connected two pins of the microcontroller MSP430F132 at the same time.

MotorDriverDesign_1.pdf

  • Hi Mert,

    At a very quick glance I think your schematics look reasonable, but I will aim to review it in more detail and provide feedback in the next couple days.

    Best,

    Davis

  • Hi Mert,

    The schematic for the motor driver looks fine, the only consideration I would keep in mind is that the resonant frequencies of the power supply bulk capacitors are all the same for the 100uF caps, so reducing the number of those and having a 470uF cap like in the TIDA-00774 might help with some very low frequency noise on the supply. As for IA_IDC, it looks like it is used to do both current sensing on the A phase and overcurrent sensing for the whole system, which is why it's connected to multiple ADC's on the MSCP430. Additionally, keep in mind your IDRIVE settings when trying to control 3 MOSFETs in parallel (refer to this app brief for more information: https://www.ti.com/lit/ab/slvaf39a/slvaf39a.pdf?ts=1718374082655).

    Best,

    Davis

  • Hi Davis,

    Thank you for your reply, but I still need to ask why IA_IDC is also connected to comparator input, cannot we just evaluate it in the code of MSP430.

    Additionally, I have already added some 180uF capacitors, but will also consider adding some 470uF bulk capacitors as you suggested.

    Moreover, I just used some calculations that the output source and sink current of DRV8353 will be sufficient to drive 3 MOSFETs in parallel.

    I have also already reviewed that material you suggested for some gate resistor choices, like if one MOSFET needs 10 ohms resistor, I added three 33 ohms resistors to each MOSFET. I have also considered to put an additional source and sink resistor with diode which are common to every MOSFETs (which I am not sure %100 if I am correct).

    Last but not least, I also wanted to ask if you could suggest any material documents, or videos that I can consider for PCB design of my motor controller which will drive 72V 3kW motor.

    Consider me as a literal beginner of Altium Designer for PCB design.

    Thank you really much for all of your advices, and in advance for your oncoming advices, hope I do not bother you really much,

    Mert

  • Hi Mert,

    IA_IDC is connected to the comparator input for just the overcurrent protection mentioned in the reference design. When the current across the shunt resistor measured by IA_IDC passes above the voltage reference in the comparator, the comparator trips a fault in the MSP430 code. It is used for ADC and more information can be found in section 6.9.13 of the datasheet: https://www.ti.com/lit/ds/symlink/msp430f5132.pdf?ts=1718632982745&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FMSP430F5132.

    Your setup of the source and sink resistors and diode looks correct, you can also refer to this app note for more detailed information on best practices for half-bridge schematics in high power designs: https://www.ti.com/lit/an/slvaf66/slvaf66.pdf?ts=1718633504032.

    Lastly, please refer to this other app note for more information on layout best practices: https://www.ti.com/lit/an/slva959b/slva959b.pdf.

    Best of luck in your design and let me know if this answers your questions!

    Best,

    Davis