ArticCynda
Advanced Member level 1
Hi all,
I have a LED panel that started flickering, and I'm trying to diagnose the problem. Picture attached. The circuit is extremely simple: 220V AC is passing through a 2.2 ohm resistor into a small bridge rectifier. Varistor across the rectifier inputs, a small capacitor and 2M resistor across the rectified AC output.
The 72 LEDs are arranged in parallel in pairs, and there are 36 pairs in series. I presume the pairs are intended as a kind of "redundancy". The anode of this massive LED series string is tied to the rectified AC output of the bridge rectifier. The cathode of the string is going to the SOIC-8 packages on the right. All 4 chips are identical, are wired in parallel to each other, and each has a bias resistor of 20 ohm and 22 ohm respectively. Because they are in series with the LED string, I assume they must function as some kind of current source.
The inscription of the ICs, which are identical, is "1952-LF". I've tried to search online but had no luck finding anything.
I'm suspecting the flickering may be caused by overheating of the current regulator ICs, so I'd like to buy 2 more and populate the empty positions on the PCB to reduce the current through each of the parallel current regulators. But for that, I'll need to find them, of course.
Does anyone here have suggestions on manufacturers of such current regulator chips, perhaps point me in the right direction, or suggest pin compatible alternatives?
Many thanks in advance,
AC
I have a LED panel that started flickering, and I'm trying to diagnose the problem. Picture attached. The circuit is extremely simple: 220V AC is passing through a 2.2 ohm resistor into a small bridge rectifier. Varistor across the rectifier inputs, a small capacitor and 2M resistor across the rectified AC output.
The 72 LEDs are arranged in parallel in pairs, and there are 36 pairs in series. I presume the pairs are intended as a kind of "redundancy". The anode of this massive LED series string is tied to the rectified AC output of the bridge rectifier. The cathode of the string is going to the SOIC-8 packages on the right. All 4 chips are identical, are wired in parallel to each other, and each has a bias resistor of 20 ohm and 22 ohm respectively. Because they are in series with the LED string, I assume they must function as some kind of current source.
The inscription of the ICs, which are identical, is "1952-LF". I've tried to search online but had no luck finding anything.
I'm suspecting the flickering may be caused by overheating of the current regulator ICs, so I'd like to buy 2 more and populate the empty positions on the PCB to reduce the current through each of the parallel current regulators. But for that, I'll need to find them, of course.
Does anyone here have suggestions on manufacturers of such current regulator chips, perhaps point me in the right direction, or suggest pin compatible alternatives?
Many thanks in advance,
AC