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DRV8353R: The VCP,VGLS voltages are low & BLDC motor is not run...

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Hi, 

We have developed a DRV8353RS EVK based custom board. In that, we have successfully communicated to DRV8353RS via SPI & Set "0x20h" value in  "Control Register 2" register for 1x PWM Mode. 

The PWM is applied to the INHA pin. But the BLDC motor is not run. While testing we found the "Status Register 0" holds the value is "0x400"(Fault register is set) & the "Status Register 1" has "0x40"( Indicates VCP charge pump and/or VGLS Undervoltage fault condition ).

We have checked the DRV controller input voltage is 24V. The VCP voltage is (with respect to Vdrain) 1.7V & VGLS voltage(with respect to Ground) 2.6V.

Could you help us to debug this issue?. If you required schematic then we will share you. 

 
Regards,
Suresh.




  • Hi 

    Find below our custom board schematics DRV8353RS sections for your reference,

    AIO-MC-BLDC-D-100V-50A-1R1.0.pdf

    Regards,
    Suresh.

  • Suresh,

    Thanks for posting on the Motor Drives Forum.

    Could you include the capacitor voltages ratings and capacitance values in the schematic? It would be helpful to check these.

    What IDRIVE do you have programmed?

    What FET model number are you using? Do you have both parallel FETs installed?

    Regards,

    -Adam


  • Hi Adam,

    Q1: Find the updated Schematics file AIO-MC-BLDC-D-100V-50A-1R1.0-50-0002.pdf for your reference.

    Q2:  IDRIVEP_HS : 300 mA  IDRIVEN_HS: 600 mA   

    Q3: Yes. We have installed 2 nos of MOSFETs in parallel. MOSFET Part Number: BSB056N10NN3 G

    Regards,
    Suresh.

  • Suresh,

    Your total Qgd represented on each gate output is 9.7nC x 2 or about 20nC. This means that for a very fast rise time of 100nS you should use no more than 200mA IDRIVE. I would say that you likely have two issues here, the IDRIVE is too high which has likely damaged the device, also when using more than one FET, gate resistors are highly recommended. Without these two things there is probably ringing and oscillation on the gate and source lines of the FETs which will kill the driver's charge pump circuit and present the fault you are seeing.

    As for the gate resistors I'm mentioning, We typically recommend 3-10 ohms in series for each FET gate. This ensures that the slightly different parasitics of each FET do not cause one FET to turn on before the other which would cause the two to fight for gate charge. 

    Regards,

    -Adam

  • Dear Adam,

    Thanks for the reply.

    We have swapped the DRV8353RS with DRV8353RH (Hardware Control IC). Same circuit worked fine and

    the motor is running.

    Below is the configuration settings for the Hardware Version IC.

    MODE,VDS,IDRIVE and GAIN Pins - Hi-Z

    We have configured the SPI IC with the below configuration. Yet we could not get the motor running.

    Also, we have removed one of the parallel mounted MOSFETs and checked. Still motor is not running.

    It is getting stuck after the initial movement.

    Please review the Register values and let us knoiw if any further settings to be configured.

    Gate Drive HS Register (address = 0x03h)

    -----------------------------------------
    LOCK = 011
    IDRIVEP_HS or IDRIVEP_LS = 0100
    IDRIVEN_HS or IDRIVEN_LS = 0100

    011 0100 0100 = 0x344

    Gate Drive LS Register (address = 0x04h)
    ----------------------------------------

    CBC = 1
    TDRIVE = 11
    IDRIVEP_LS = 0100
    IDRIVEN_LS = 0011

    111 0100 0011 = 0x743
    OCP Control Register (address = 0x05h)
    --------------------------------------
    TRETRY = 0
    DEAD_TIME = 01
    OCP_MODE = 01
    OCP_DEG = 10
    VDS_LVL = 0111

    001 0110 0111 = 0x167

    CSA Control Register (DRV8353 and DRV8353R Only) (address = 0x06h)
    ------------------------------------------------------------------
    CSA_FET = 0
    VREF_DIV = 1
    LS_REF = 0
    CSA_GAIN = 10
    DIS_SEN = 0
    CSA_CAL_A = 0
    CSA_CAL_B = 0
    CSA_CAL_C = 0
    SEN_LVL = 11

    010 1000 0011 = 0x283

    With Best Regards,

    B.Saravana Vikram.

  • Vikram,

    With the SPI device, are you reading out any fault code on register 0x0 or 0x1?

    What is your configuration for 0x2? This register will set the PWM MODE, COAST, BRAKE, etc.

    Your IDRIVE is likely still too high at 300/600mA. Please check the gate and source nodes for rining/overshoot/undershoot as this can damage the device if the ABS max is violated.

    Regards,

    -Adam