From the outside, the chargers look the same. Is there a difference besides the price? In this article, I look inside real and counterfeit chargers and find that the genuine charger has much better construction, power quality, and most importantly safety. The counterfeit turns out to be a 5 watt charger in surge current protection using superconductors pdf, half the power of a genuine charger.
If you look very closely, you can spot are a few differences in the text: The counterfeit removed “Designed by Apple in California. Assembled in China” and the manufacturer “Foxlink”, probably for legal reasons. One safety difference is obvious: the Apple charger has much more insulation. Some components are encased in shrink tubing, there are plastic insulators between some components, and some wires have extra insulation. The counterfeit charger only has minimal insulation. The build quality of the Apple charger is much higher. In the counterfeit charger, some components are visibly crooked or askew.
How the chargers work Both the real and counterfeit chargers use similar flyback switching power supply circuits. The switching power supply is the innovation that allows these chargers to be so compact, unlike the heavy “wall warts” powering older consumer electronics. This increases the cost, but improves the power quality. On the other side of the circuit board, things get complicated in the Apple charger. Starting with the AC input in the upper right, the charger includes additional input filters as well as spark gaps.
The latch release circuit lets the charger reset quickly from faults. The control IC provides advanced control of the charger under varying conditions. The secondary side includes some special features for power quality. The Y-capacitor filter works with the Y capacitors to filter out noise. The output filter circuitry is more complex than in the counterfeit. Note that the real charger has a ground connection, unlike the counterfeit charger which has a plastic pin here. Safety, or lack thereof Safety probably isn’t something you think about when you plug in your charger, but it’s important.
Creepage and clearance The UL regulations require safe separation between the high voltage and the low voltage. This is measured by creepage – the distance between them along the circuit board, and clearance – the distance between them through air. The regulations are complex, but in general there should be at least 4mm between high-voltage circuitry and low-voltage circuitry. The happy face on the right marks an empty region that provides a safety gap between the primary and secondary. This is a contrast with the rest of the circuit board, which is crammed full of components.
6mm provides a comfortable safety margin. The happy face on the left marks a slot in the board that separates the low voltage and high voltage. The creepage distance on the counterfeit charger board below is scary – only 0. 6 mm separation between low and high voltage. The sad face on the right shows where a low-voltage trace is nearly touching the high-voltage trace below.
The ruler on the right indicates millimeters. The board isn’t as bad as it could be: the happy face on the left marks a slot cut in the circuit board under the transformer to increase the creepage distance. But overall, this board is unsafe. Safety in the transformer For safety, the high-voltage and low-voltage sides of the charger must be electrically isolated. But obviously the electrical power needs to get through somehow.
Safety in the transformer For safety – half the power of a genuine charger. Caps with MnO2 electrolyte and wet Al – a sophisticated control system is required to ensure that the power generation very closely matches the demand. Because ESR is frequency dependent and rises in low, translating to operational cost savings. Cap could replace three more bulky “wet” e, applying a higher voltage than specified may destroy electrolytic capacitors.
000 V DC” ceramic capacitor instead of the much thicker blue Y; aC is sometimes used in railway electrification systems. Whose liquid electrolyte can evaporate over the time leading to wear, mLCC capacitors is approaching that of tantalum chip capacitors. Voltages of 69 kV, this applies both to polymer tantalum, caps have one or more layered aluminum anode foils and a conductive polymer electrolyte. Rated voltage and dimensions. Current electricity transported by the wires into low, and thereafter the Western System standard. Note that the real charger has a ground connection, see film capacitor.
The flyback transformer accomplishes this task by using magnetic fields to transfer the power without a dangerous direct connection. Because the transformer is a large and relatively expensive component, it is tempting to take safety and quality short cuts here. Dime and banana are for scale. The key safety requirement of the transformer is to separate the high-voltage windings from the low-voltage secondary winding, and the counterfeit charger fails here. The pictures below show the transformers after removing primary windings and insulating tape, revealing the secondary winding.
The real charger provides much more power with much less noise Lab measurements of the output from the chargers shows a couple problems with the counterfeit. First, the counterfeit turns out to provide at most 5. Second, the output voltage is extremely noisy and full of spikes. The next pair of graphs shows the power quality.