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DRV8801: nFAULT detection & Increasing RPM

Part Number: DRV8801
Other Parts Discussed in Thread: TIDA-00875,

Hi, 

One of my customer designed a single phase BLDC operated on 12V using DRV8801 with reference from TIDA-00875. 

1. When i try to stop the fan blades physically using some obstacle like screw driver or pencil, the motor stops, and then starts moving again after I remove the obstacle, which is good. But there is no any indication on nFAULT pin in this case, nFAULT remains HIGH. Can this condition be detected using nFAULT?

2. Customer wanted to increase the RPM for the same blades connected to the motor. Please suggest on this. 

  • Hi Naveen,

    Naveen Bevara said:
    1. When i try to stop the fan blades physically using some obstacle like screw driver or pencil, the motor stops, and then starts moving again after I remove the obstacle, which is good. But there is no any indication on nFAULT pin in this case, nFAULT remains HIGH. Can this condition be detected using nFAULT?

    There may be no indication of a fault. As long as the voltage remains high, the current remains below overcurrent and the temperature remains below the overtemp warning, nFAULT will not assert.

    Naveen Bevara said:
    2. Customer wanted to increase the RPM for the same blades connected to the motor. Please suggest on this. 

    How are the inputs being controlled? Are they at 100% duty cycle?
    If the device is operating at 100% duty cycle, the only method to increase the speed is to increase the voltage.