Hi,
I'm working on a power protection circuit using the LTC4368:
The input voltage can swing from 12V to 38V, with a nominal voltage of 24. The circuit after the LTC4368 is a dc-dc regulator, with is own input filter:
Ideally, the circuit must trip for an overcurrent of 1A. As it is from the schematics, the circuit works without a load attached after the dcdc. If a load is connected, even a light of 100-200 mA, the circuit does not work and the output voltage does not ramp up. The LTC4368 does not indicate a fault, but the mosfet seems to be not fully closed, as the input and output LED flickers with low light.
I have tried to change Cgate to 3.3 nF, and to reduce the Rsesne to 22 mohm, and the startup with load seems now to work properly, until circa 30V.
If an overvoltage fault trigger, the same problem appears, when the voltage falls below 38V the fault disappear but the mosfet will not turn on again, until the voltage decrease below 20/22 V.
With UV fault, the circuit jst works fine.
What could be the problem?
