Good evening, I have a strange problem with a circuit board using this integrated circuit.
I made 40 copies of a controller board for a LED strip Bridgelux BXEB-L0280, which operates at approximately 21 volts and 670 mA. They work perfectly connected to 48-volt power supplies (and I even tried up to 53 volts), the operation is stable and without problems. All work like a charm whith an efficiency near of 95%. Perfect.
The problem begginns when I try to connect the exact same boards to a 48-volt battery system, as soon as the power switch is activated, if there are one or two boards connected, it works perfectly, but if there are more, the MP24833 IC immediately explodes, even with the on/dim pin connected to ground and no voltage applied. I repair the damaged boards by replacing the integrated circuit, test them again with another power supply, and they work perfectly. I reconnect them to the other power supply, and as long as I connect one or two at a time, there is no problem.
I already checked the battery line voltage with an Agilent U1253 tester, and it’s slightly below 48 volts. I also checked with an oscilloscope that the voltage was clean of parasitic signals, and it is. Since the line is long (at least 30 meters), I did observe a slight transient when the line was energized, but it doesn’t exceed one volt in amplitude. I’ve already destroyed 22 circuit boards (well, only the mp24833, rest of components are harmless) and I’m completely baffled. They all work fine individually, but when connected to the same circuit they burn out as soon as I flip the switch, unless it’s just one or two, in which case they work perfectly and as expected.
This is the schematic (essentialy the same in the datasheet) and the PCB is single side, I can upload if it is neccesary. I’ve tried with and without populating R1, same behavior. Sorry the typo, C2 it´s 4.7uF
Any suggestion or help would be appreciated, Thanks in advance
