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TIDA-01485: Questions

Prodigy 220 points

Replies: 1

Views: 583

Part Number: TIDA-01485

Hello,

I had this PCB built for educational purposes, but I have not been able to get it to work. I have a few questions.

(1) SL_C is shown connected to C18 to the right of the Phase B power block. I am questioning this since SL_A is shown connected to C19 next to the Phase A power block and SL_C is again shown connected to C22 next to the Phase C power block.

(2) I am somewhat confused by the notes below the 3-phase gate driver on sheet 1 and the note pertaining to R17 and R18 below the current sensing circuit on sheet 4. I am just trying to use the PCB and firmware code "as-is", and I am not sure which components should or should not be installed based on the current design.

(3) I am also curious if there are any specific reasons why the MSP430F5132 was chosen for this design. Is there anything that makes it more conducive for this specific design over all the other variations of MS430 micro controllers? I would like to try to port the firmware code over to Energia once I can the PCB working using the program developed in CCS. However, it appears as though there are only a select number of MSP430 micro controllers that are compatible with Engeria and the MSP430 Launchpad, and the MSP430F5132 is not one of them.

Thanks,

  • Hi Scott,

    Please find below my comments to your questions.

    1. C18, C19 and C22 are decoupling capacitors (decaps) for each leg of the power stage. For example. C18 is the decap filter for the PHASE B power block that is U2, which should be placed across U2 and  close to U2.The same is the case with PHASE A and PHASE C. Which means C18 is for U1 and place close to U1 and C22 is for U3 and to be placed close to U3. This will help in getting clean switching waveforms.


    2. The schematic shows the "DO NOT POPULATE" components with a red cross. The same can be validated against Assembly drawing and the BOM. The default "DO NOT POPULATE" components are mentioned in the BOM with "Quantity" zero. The notes below the 3-phase gate driver, is provided for different configurations, which the board can support. Please go through the datasheet of DRV8323 to understand more on these configurations.

    On current sensing, the default configuration senses the drain to source voltage of low side FETs for current sensing. That is why you see R17 and R18 as "DONOT POPULATE", and the same is commented below the sense resistors.


    3. The MSP430F5132, was selected because of many reasons: the availability of required peripherals like the TIMER D, port mapping functionality, internal over current detection comparator, Number of GPIOs, 25MHz frequency etc. The existing code and layout support only this device/family. I recommend to use the CCS IDE to evaluate the board. The firmware available on TIDA-01485 page can be used.
    You can use other family of devices also like the MSP430G series. But the existing layout may not support device and you may have to develop new board for the same.

    Hope it clarifies your questions. Let us know if any further questions.


    Thanks,
    Manu

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