High-quality imitation Macbook chargers: Shiny on the outside but very dangerous on the inside!

What's inside a counterfeit Macbook charger? A reader sent me a charger he suspected was a counterfeit. On the outside, the charger looked like a near-identical Apple charger, but when you take the charger apart, the inside is very different. It has a much simpler design, lacks the quality features of the genuine charger, and has major safety flaws.

Inside the fake MagSafe 45W charger. Fake Apple chargers I've seen in the past usually have external flaws that give them away, and you can tell by looking at them. But this charger might be able to get away with it. The external text on this charger is correct, with the same "Designed by Apple in California" text as the genuine charger. Unlike many fakes, it has a metal ground pin (although it's not connected internally), which fakes often exclude. To the right of the ground pin, the serial number sticker is a bit crooked, suggesting a problem. It has an embossed Apple logo on the case. The charger is not lightweight. There are so many online teardowns of fake chargers that I wonder if the manufacturer has learned anything from those articles. One minor flaw is that the serial number sticker (to the right of the ground pin) is a bit crooked and doesn't stick well.

The fake MagSafe 45W charger has the same "Designed by Apple in California" text as the genuine charger The image below shows the safety certification the charger claims to have. Again, it looks authentic, with no typos or ugly fonts.

The fake power bank has all the same safety instructions as the real one. One flaw that made the netizen buyer suspicious is that the quality of the casing does not seem to meet Apple's standards. It doesn't feel much like his old charger when tapped, and the connector looks a bit asymmetrical, as shown in the picture below. (Unscrupulous merchants saw this and made the fakes more realistic, putting some iron blocks inside to increase the weight)

The seams on the fake Magsafe power supply are a bit asymmetrical.

The problem came when I plugged in the charger and measured the output of the Magsafe connector. An output voltage of 14.75 volts was measured, and when I shorted the pins together, sparks appeared. Since the charger is rated for 14.85 volts, this seems normal, but it is different from the behavior of a real charger. The Magsafe charger initially produces a low-current output of 3 to 6 volts, so shorting the output should not produce sparks. The charger switches to full output power only when the microcontroller inside the charger detects that the charger is connected to a laptop, which is a safety feature of real chargers that reduces the risk of shorting between pins. The counterfeit charger, on the other hand, omits the microcontroller circuitry and simply outputs full voltage all the time. This increases the risk of burning up the laptop if you insert a connector that is bent or metal fragments stick to the magnet.

Inside the charger

Use a hammer to open the charger and you can see the internal circuit. The real Apple charger has a very complex circuit inside, but the board density of this charger is quite low, it is just a simple flyback switching power supply .

Fake MagSafe charger with the case and heat sink removed

The circuit is a fairly standard flyback power supply. To understand how it works, look at the diagram below, going counterclockwise from the AC input on the right. After power passes through the fuse , it is converted to DC by a bridge rectifier . A large filter capacitor smoothes the DC. Next, a switching transistor chops the DC into pulses, which are then fed into a flyback transformer . The transformer's low voltage output is converted back to DC by the output diode, which outputs smooth DC after passing through the output filter capacitor .

The fake Magsafe power supply uses a standard flyback switching power supply circuit.

The feedback TL431 is a voltage reference that feeds into the feedback signal that controls the IC via an optoisolator. While this circuit looks complicated, it is pretty standard for a simple charger. On the other hand, as I describe in my teardown, the circuitry of a real Macbook charger is much more complicated.

The charger is controlled by a tiny 6-pin IC on the bottom of the board . It turns the MOSFET on and off at the appropriate rate (about 60 kHz) to produce the desired output voltage. The control IC is printed with "63G01 415", and a clever netizen identified the chip as OB2263. (Here I would like to state that Onbao's power chip is still very good and has a high cost performance, but it is not suitable for use here)

Close-up of the tiny control IC inside the fake MagSafe 45W power supply

What's wrong with this charger?

One of the most important features of a charger is the safe isolation between the potentially dangerous AC input and the low voltage output. There should be a safe gap of at least 4mm between the high and low voltages (to simplify UL's creepage and clearance rules). In the board below, the high voltage input section is on the bottom and the low voltage output section is on the top. On the right half of the board, there is a large gap between the two sections, which is fine. On the left side, there should be a gap (bridged by the optoisolator). Unfortunately, traces and components pass through this area, making the gap as small as less than 1mm, which is very dangerous. Any moisture or loose solder can bridge this gap and output a high voltage to the output.

A counterfeit MagSafe charger has very little clearance between the low voltage side (top) and the high voltage side (bottom) One of the more confusing aspects is why counterfeit chargers never manage to have enough safety clearance. They use simple, low-complexity circuits, so the board layout should be simple. Except in the smallest cube phone chargers, they don't fight for every millimeter of space.

The second safety flaw is the heat sink that provides cooling for the input side MOSFET and output side diode. The heat sink is basically on both sides of the circuit with only a small gap separating it from the rest of the circuit.

In addition to having large creepage and clearance between high and low voltage, the real charger also uses a lot of insulation tape for isolation. The counterfeit charger lacks additional insulation except for heat shrink tubing around the fuse and fusible resistor. I did not disassemble the transformer, but I expect it also lacks the necessary insulation.

The fake charger has a metal ground pin (unlike other fakes I've seen that have a plastic pin). However, the pin is only for appearance and is not connected to anything.

The image below compares the underside of a counterfeit 45W charger (left) and an authentic Apple 60W charger (right). As you can see, the counterfeit has a simple circuit board with only a few parts, while the authentic charger is crammed with parts. These two boards are in completely different worlds of design complexity. The additional parts allow for better power quality and greater safety in the authentic charger, which is part of the reason why the authentic charger is noticeably more expensive.

Genuine chargers are crammed with parts, while counterfeit chargers only have a few parts.

Power Quality

I measured the output power of the fake charger with an oscilloscope , and as shown below, the output is not smooth, and there are pairs of large spikes when the switching MOS tube is turned on and off. The charger runs at a frequency of about 60 kHz. More filtering inside the charger can reduce these voltage spikes, but it costs more.

Generates large voltage spikes

The scope trace below zooms in on one of the spikes. You can see that the peak-to-peak value of the spike is 2.7 volts, which is a lot of noise going into the laptop.

The counterfeit charger's output has a large 2.7V noise spike.

 in conclusion

This fake Magsafe charger looks convincing from the outside, with more attention to detail than most. It wasn't until I opened it that I was completely sure it was a fake. But inside, the difference between the fake charger and the real thing is clear. The fake has simpler circuitry that delivers poorer quality power. It also ignores safety regulations, putting you and your computer within a millimeter of a dangerous shock. While fake chargers are much cheaper, they're just as dangerous to you and your computer.

 The knockoff is not a charger, it is a regulated power supply . Only lead-acid batteries can be charged at a constant voltage (with the correct settings), and it can be charged, but without any protection it is very dangerous. Also, this knockoff is not "cheaper", it is the wrong species. Price comparisons are irrelevant unless conditions are the same. Such a power supply is likely to damage your computer and even cause a fire.