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CSP and CSN of UCD7231 short to GND

Other Parts Discussed in Thread: UCD7231


We found problem on UCD7231, CSN and CSN  of UCD7231 short to GND. just would like to check with TI, without the RSH_Sense could affect VGG, CSP, CSN short to GND or not.  now we do not a resistor from HS sense pin to the drain of high side mosfet and found this kind of issue.

Best Reagrds,


  • I'm not sure if you are indicating that the HS_Sense is left open or is connected directly to the HS mosfet drain without the RSH_Sense resistor, so I've included both answers.


    Leaving the HS_Sense pin on the UCD7231 driver floating if the RSH_Sense resistor is not present may cause erratic FLT fault reporting if noise is being picked up by the pin.  It is recommended that the HS_Sense be used with the value of RSH_Sense resistor as calculated from the UCD7231 datsheet but if HS_Sense is not used then it should be tied to ground through a pull-down resistor.  Leaving HS_Sense disconnected should not effect the operation of VGG, CSP or CSN.


    If HS_Sense is connected directly to the drain of the high side fet without an RSH_Sense resistor then the driver will report a FLT fault whenever the HS mosfet is switched.  The RSH_Sense resistor sets the maximum allowed voltage drop across the HS mosfet (after the HS blanking interval set by RDLY) as sensed at the SW pin.  Connecting it directly to the drain of the HS mosfet will set the FLT trip point at the input rail voltage resulting in any drop across the HS fet during its on time to be interpreted as an over-current (OC) condition.

    The UCD7231 was not designed to have HS_Sense connected to the drain of the HS mosfet without an RSH_Sense resistor and will cause the driver not to function correctly but this should not effect the operation of VGG, CSP or CSN.


    Exceeding the Absolute Maximum Ratings of any pins could result in damage or degraded operation of the driver.