Fake Samsung charger with interesting circuitry

I had another go at getting this thing to communicate with various devices and step the voltage up for higher power delivery, but drew a blank. It just didn't happen.
It would have been handy to have a USB-C breakout PCB to check voltages, since the middle output didn't seem to activate at all, even for 5V.

This is one of many clone power supplies being sold on eBay at a higher price than a safe and compliant charger from somewhere like IKEA. There's absolutely no guarantee of safety with the grey import units. A good USB charger is an essential part of modern digital life, so it pays to get a good one and also a decent cable for your higher power items. These units from unaccountable sellers often pose a high shock and equipment damage risk through cost cutting and bad design.

The circuitry is quite intriguing because of the way they have implemented the ability to initially have a standard 5V supply, but then allow two different ICs to negotiate a higher voltage with the connected equipment and then override the preset 5V reference to raise it to the desired level.

The two power supply modules are quite unusual for having separate rectifiers and smoothing capacitors on the primary side. They could have used a single rectifier and smoothing capacitor. I wonder if it's to avoid interaction, or just based on a duplicated single power supply design.
The use of a TL431 shunt regulator with a near-50/50 divider to hit its threshold of 2.5V with a supply rail of 5V is quite neat.
The primary side control chips are almost certainly a clone of another prominent IC like a Viper 22A


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