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DRV8718-Q1: Overcurrent detect

Link Huang
Expert 6255 points
Part Number: DRV8718-Q1

Hi expert,

The customer performs an over current diagnostic test with drv8718-Q1 operating normally.
The BRG_CTRLx channel control register is set to control channel output. The VDS_CTRLx, VDS overcurrent detection registers are set. Where the VDS register value is set to 1V.

  
However, when overcurrent is detected, the device does not feedback a VDS error. Instead, a PVDD error is being reported.

  • If they want to do the over current diagnostic of channel output, is there any other registers to be configured in addition to these two registers?
  • Is Offline diagnosis of the channel always performed with the channel at high resistance?

BR，

Link

  • 0
    TI__Guru 55615 points

    Hello,

    Can they check PVDD supply voltage?  It is possible to get a PVDD error if the supply falls under a heavy load condition like a short condition.  If the power supply is unable to supply the current, the PVDD supply will collapse and cause an error.

    Regards,

    Ryan

  • 0 in reply to Ryan Kehr
    TI__Expert 6255 points

    Hi Ryan，

    The current test circuit is directly shorted to ground, thus resulting in a heavy load condition.

    May you please help me to understand those questions:

    • if they want to test over-current detection, how should the external test circuit be configured?
    • If they want to do the over current diagnostic of channel output, is there any other registers to be configured in addition to these two registers?
    • Is Offline diagnosis of the channel always performed with the channel at high-resistance?

    BR，

    Link

  • 0 in reply to Link Huang
    TI__Guru 55615 points

    Link,

    The power supply just needs to be capable of providing the current that occurs during a short. 

    Please see the following section in the datasheet that discusses which registers need to be configured.

    8.3.8.8 MOSFET VDS Overcurrent Protection (VDS_OCP)

    Yes, the outputs must be disabled so internal current sources used for offline diagnostics can be used.

    Regards,

    Ryan