I am running into an issue where the output of the MP5056 gets disabled when the input is re-connected while the output is discharging.
I originally ran into the problem when a long input “bounce” would disable the output but have managed to replicate it by disconnecting power and quickly re-applying power. I have captured the behaviour here where the yellow is VIN and blue is VOUT
I have it set to not auto-retry on a “fault” but I do not really see this as a fault event, and cannot see anything related to power disconnect behaviour in the datasheet.
The voltages don’t appear to exceed the absolute maximum thresholds of the MP5056.
I am curious about the current in application. What is the load current? In addition, what is the current limit set to? My first inclination is that there could be a current inrush that could be overloading upon start-up.
The current limit is set to 12.5A (10k resistor), and appears to be working correctly as the VOUT rises slower than the VIN. It is only on the rapid disconnect and re-connect that it problem occurs.
The load is approx 500uF of capacitance, with almost no load after the initial inrush.
FLTB is being pulled low but there is no overcurrent event (the capacitive load will still be charged and no current spike shown on IMON). So not sure why this is being treated as a fault.
Interesting. Thanks for providing more waveforms showing this behavior.
The FLTB pin should only be pulled down if an OC Fault occurs or if a thermal shutdown fault occurs. Based on the nature of what is happening, it seems like it would make more sense that we would be experiencing an OC event.
Also to focus more on what could be going wrong, do you have a schematic of the MP5056 with respect to what is happening here?
The behaviour is very repeatable, and only occurs if VIN is re-connected whilst VOUT is discharging. If it is reconnected slightly later after the discharge (when I would expect a larger inrush) it does not cause a fault
