I am using the TPS92692 in buck-boost mode with an analog signal to set Iadj and PWM. When I start the circuit, it consistently goes into fault mode and the fault pin is periodically set low. However, after about 5 seconds, everything works fine and the fault pin is no longer set low but after some time, the current also gradually decreases.

The input voltage is 24 V and the circuit powers 7 LEDs (with a forward voltage range of 2.8-3.4 V for each LED). In this case, Iadj is set to 1.46 V and the PWM is 2.44 V

Here is the circuit:

Current start-up signal (yellow) and fault pin signal (purple) :

Current after about 5 s:

The datasheet of the IC indicated that there is 4 fault conditions :

• Overvoltage across the LED string (VOV> 1.24 V)

• Under voltage across the LED string (VOV< 100 mV)

• Overcurrent across the LED string (14 × V(CSP-CSN) > 1.5 × VIADJ)

• Cycle-by-cycle switch current limit condition (VIS > 250 mV)

As far as overvoltage and undervoltage are concerned, everything seems to be fine, the voltage is below and above the condition when the pin is on fault:

It is more difficult to say about the cycle-by-cycle switching current limitation condition, because the signal is really noisy:

F.Cu :

Inner1.Cu :

Inner2.Cu :

B.Cu :

I also noticed that the RSlope should be 180 kohm instead of 150 kohm. I'll try changing the resistor to see if there's any impact.