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DRV8307: Drive waveform

Part Number: DRV8307
Other Parts Discussed in Thread: DRV8306

Hi Team,

Customer would like to know if DRV8307 is not connected to the Hall signal, is there any way to test the drive waveform? Now he does not connect the Hall signal, or connects to the Hall signal sent by other external drivers, and then inputs the pwm waveform 20k, it will alarm. What is the reason for the alarm? How to better match the Hall signal on the motor? He wants to test the six-channel drive waveform, there will be no drive waveform output after an alarm.

Thanks,

Annie

  • Hi Annie,

    If the Halls are not connected, The device will be in STATE 1X or 2X - please see table 1 on page 13 of the datasheet. These combinations are not allowed and will result in a fault (see note 1 under the table)

    I would recommend putting some signal on the Hall inputs (i.e. HALLA = 0, HALLB = 1, HALL =0) because then the output will result in a PWM signal.

    Bear in mind the DRV8307 does have a locked rotor detect - if it detects that the Halls are not transitioning for 3 seconds, it will cause a fault. For DRV8307, it is best to test the device with some rotating motor.

    You can also check out DRV8306, which is the newer version of DRV8307. The DRV8306 does not have locked rotor detect and therefore you can test it this way.

    Thanks,

    Matt

  • Hi Matt,

    The customer connects the Hall signal on the bottom of the motor to DRV8307 in the way shown in Figure 12. Hall ABC is connected to pull up 4.7k to 5V, and then sent to Hall signal positive. Hall signal negative is all connected to 2.5V after 5V divided voltage. This Hall signal is generated by other DC brushless drivers, and then passed to drv8307. Test, there is a Hall signal, and the 16-pin output of the chip also has a Hall signal output. As long as the 20kpwm signal is not input to the 19-pin pwm, there will be no alarm. Once the signal is input, it will alarm. The customer thinks that there is a Hall signal input now, but why does it give an alarm when the 19-pin input signal is input? 

    The measurement alarm signal is a 5US high and 5ms low. In this case, his six-channel drive waveform output will only output the drive waveform when 5US is high (there is no alarm at this time). That is, the time when the waveform is turned on is consistent with the timing of the alarm signal. Customer wants to know why?

    He can only test on drv8307 now. How to test the Hall signal from other drivers outside? And which connection method is better for the Hall signal?

    Thanks,

    Annie

  • Hi Annie,

    This sounds like motor overcurrent (see Page 18, section 7.3.11.3. OCP has a 5ms retry time.

    What are the VFETOCP and VSENSEOCP setting? Are there MOSFETs and sense resistors connected on the output of DRV8307? If there are no MOSFETs or sense resistors, the DRV8307 will detect OCP through MOSFET VDS or sense resistor voltage and trigger the fault.

    Thanks,

    Matt

  • Hi Matt,

    Customer said his issue was resolved. 

    Thanks,

    Annie

  • Thanks Annie, please click the button to verify the answer!