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TPS2H160-Q1: TPS2H160Q1 Output Not Working with Recommended GND Network (1kOhm + Diode)

Deekshitha Sanjeeva
Prodigy 10 points
Part Number: TPS2H160-Q1


We implemented the ground reverse protection circuit as advised in the datasheet. However, we are still encountering an issue with the circuit’s behavior.
Specifically, when we connect a 1 kOhm resistor to ground as part of the protection scheme, the switch does not toggle and no output is observed, even when the input voltage is varied between high and low states. In contrast, when the 1 kOhm resistor is replaced with a 0Ohm resistor (a direct short to ground), the circuit functions correctly and the output responds as expected.
I’ve attached a screenshot of the circuit diagram for your reference. Could you please help us understand why the presence of the 1 kOhm resistor prevents the output from functioning, while a 0Ohm connection resolves the issue? Any insights into the underlying mechanism or related design considerations would be greatly appreciated.
 
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  • 0
    TI__Genius 10965 points

    Hey, 

    When implementing a GND network there is a ground potential shift. This CL pin must be routed to IC_GND when this network is applied. In addition, the IN pins have internal 175k pulldowns so external pulldowns are not recommended. I recommend removing R67 and R70 and route R71 to IC_GND and not module GND. 

    BR, 

    Alan 

  • 0 in reply to Alan Whitehead
    Prodigy 10 points

    Hi Alan,

    Thank you for your suggestion. We observed that the circuit worked when we connected the CL resistor ground directly to Pin 8 of the IC (GND). Could you please confirm if this connection might affect the current limit calculation, as the 1 kΩ resistor in the network ground would now be in series with the board ground?

  • 0 in reply to Deekshitha Sanjeeva
    TI__Expert 3620 points

    Hi Deekshitha,

    the current limit is calculated by determining the difference between the Current limit pin and the ground pin. The 1k ohm to board ground does not affect the device when it is connected as shown:

    I would recommend changing the GND24 connection point to the GND pin of the device to make sure that the current limit works accordingly

    Best Regards,
    Nicholas Petersilge