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Original question:

DRV8962: DRV8962 Parallel Outputs

DRV8962: How to diagnose STB, STG & OC faults on 4 individual output solenoid drives.

Piyush Mishra
Prodigy 10 points
Part Number: DRV8962-Q1

Tool/software:

Hi,

I'm using DRV8962-Q1 to drive 4 solenoid drives. 

1. May i know how this IC can help to detect the Short to battery, Short to ground & open circuit fault diagnostic using 4 IPROPI signal and 1 fault signal? Micro need to distinguish the fault type in my application.

2. Can this current sensing only work when we use OUTPUTs as High side drive? Is there any issue to use them as Low side drives?

Best regards

Piyush Mishra

  • 0
    TI__Mastermind 44315 points

    Hi, 

    Thank you for your post. Monday September 1st is national holiday in US. Please expect delay or please wait for our expert assignment on Tuesday US time

  • 0 in reply to Shinya Morita
    TI__Mastermind 44245 points

    Hi Piyush,

    Thanks for your question.

    1. The DRV8962-Q1 does not have a native STB (short to battery) or STG (short to ground) detection. It does have overcurrent protection OCP for each output FET, and IPROPI output for external measurement. The fault signal nFAULT reports any one of the fault conditions as described in the datasheet - see below table. The OCP detection is available for each output FETs and is independent of the IPROPI which is from HSFET current only. 

    See section 6.10.4 Overcurrent Protection (OCP) of the datasheet - shown below.

    The output STG condition would force an OCP when the corresponding HSFET is conducting. This will cause an OCP condition and shutdown the driver. When there is an STG and the HSFET is not conducting the short conditions will be undetected. The IPROPI output will be valid only while the HSFET conducts. Likewise an STB can trigger an OCP while the corresponding LSFET is conducting. 

    That said, if you need STG and STB detection while the driver output is inactive you must design an external circuit.   

    2. The internal IPROPI current sensing will only work with outputs as high side driver as described in section 6.5.1 Current Sensing and Feedback in the datasheet. You can use this device as a low side driver but it will not have any IPROPI functionality in this configuration. You could build an external current sensing as described in the section 6.5.2 Current Sensing with External Resistor of the datasheet. No other issue to use the half-bridges as low side drivers. 

    Regards, Murugavel