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TIDA-00643: LAUNCHXL-F28027 C2000 Piccolo MCU F28027 LaunchPad

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Replies: 1

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Part Number: TIDA-00643

Hi,

In reference to TIDA-00643, I am trying a design a system which can run a Brushless DC Motor with higher power.

Test Procedure :

For testing, I tried running my motor at different values of USER_MOTOR_MAX_CURRENT from 5 A to 23 A. Using a Watt-Meter I measured the current draw which was found to be pretty accurate at peaks. 

Observations :

1. It runs smoothly from 0-15 A.

2. It jitters from 15-23 A. 

3.It throws a fault when run at values greater than 23 A.

Goal : I want to increase USER_MOTOR_MAX_CURRENT  

I have three assumptions :

1. Is it any component's (i.e. DRV8305, shunt resistors, MOSFETs ) maximum rating that is limiting the USER_MOTOR_MAX_CURRENT ?

2. Is it the layout of the board that is limiting it?

2. Is it any parameter in the firmware that is limiting it?

3. Is it the thermal protection circuit in the DRV8305 that is shutting it off ?

Thanks,

Anushka

  • 1. All three factors have an impact on the maximum current.

    2. Yes, especially long-time running with a load.

    3. USER_MOTOR_MAX_CURRENT in user.h

    4. No, but will turn off the MOSFET if the Vdson is greater than limitation value. 

    Btw, you may take a look at the datasheet of DRV8305, you should find more information about your question 1&4.