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How to report LED short fault during buck & boost to battery topology?

How to report LED short fault during buck & boost to battery topology?

Infineon_Team
Employee
Employee
50 replies posted 25 likes received 25 replies posted

TLD509xEP features a threshold on FBH pin to detect the short to ground fault.

The wire harness could face a short to ground on the positive or negative output.

In Boost and Buck to Battery topologies, the device reacts to the short in the following way:

  • Boost to battery:
    • Short to ground of negative output (cathode side): FBH is connected to ground and then this condition triggers the fault
    • Short to ground of positive output (anode side): FBH is connected to ground through a protection diode DSP3; its voltage is below VFBH,FBL_S2G

Image1.png

 

  • Buck to battery:
    • Short to ground of negative output (cathode side): FBH is connected to ground and then this condition triggers the fault
    • Short to ground of positive output (anode side): No current flows on the LED then the voltage of FBH is 0V

​​​​​​​Image2.png

Anyhow, in these two configurations the device cannot detect a short on the load side (short between positive and negative terminals).

 

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