preface
For the FireWire interface, many children have not seen, this is Apple in the first and second generation of iPods used power supply and data transmission interface, support 400Mbps transmission rate, and usb 2.0 interface speed is similar. The FireWire interface, also known as the 1394 interface, has now been replaced by a USB interface. The FireWire interface supports both data and power supply functions, which is also the prototype of the modern universal interface.
The charging head network got a FireWire charger for the early iPod, and the output 12V was used for charging. In addition to powering the devices in the FireWire interface, this charger can also charge devices with 30pin sockets through the FireWire to Apple 30pin data cable. The charger is manufactured by Delta, so let's take a look at how this 18-year-old charger was designed.
Apple iPod original 12V FireWire charger out of the box
The charger that was brought back has no pin module, after all, it is a product of 2004, and it is not too much to call it an "antique". Coupled with the curiosity to disassemble this charger, it does not matter whether there is a plug or not.
Even if the prong module is missing, you can see that this charger is designed with Apple's classic square shape, the surface is high-gloss and bright, the corners are rounded, and the overall is simple and smooth. The front and back of the fuselage are designed with apple logos in the center.
The prong module is detachable, but the T-mount is made of plastic, so it only serves as a fixing function and cannot be grounded.
Printed on the side is the product information, which is the charger of the Apple iPod, model A1070.
The adjacent side is printed with charger input and output parameters, supporting 100-240V~50/60Hz 0.4A input, and 12V0.67A output, which has passed CE and UL certification.
The output end adopts the FireWire 400 interface.
The measured length of the charger body is 59.91mm.
The width is 59.74mm.
The thickness is 28.39mm.
Compared with apple 30W charger, the overall is a little larger.
The size of the hand is intuitive.
The charger with the pin module removed weighs about 78g.
Apple iPod original 12V FireWire charger disassembled
After a basic understanding of Apple's charger, the following charging head network continues to disassemble it, let's see how it works.
First of all, the charger shell is disassembled, the charger adopts the classic two-piece structure, and the internal PCB module wraps the insulation sheet and the heat sink to dissipate heat.
The output firewire interface is soldered to a small PCB, the PCB is fixed to the housing by screws, and the PCB uses a single panel, which is difficult to see in modern chargers.
Unscrew the fixing screws and use an insulating plate under the firewire interface to isolate.
Remove the internal module of the charger, and the heat sink plates on both sides of the module are glued and the housing is fixed.
The back of the PCB is also covered with heat sinks and insulating plates.
The input PCB has an isolation slot and the wire pressure terminal is soldered.
The output terminal wires are also pressed terminals and soldered to the PCB.
The heat sink is soldered to the pin of the Y capacitor.
The input and output leads are welded off, and the transformer is connected to the heat sink through the thermal conductive adhesive to dissipate heat. The fuse, X capacitor, and common mode inductor can be seen at the input, and the primary filter capacitor is fixed to the PCB using glue.
Leave the place where the output side corresponds to the fire wire socket blank, and fix the fire wire socket.
FireWire socket small board close-up, socket from AMP amp, is a well-known American connector supplier.
After years have passed, the gilded color inside the socket remains the same.
It has been observed that this power supply uses an RCC switching power supply, does not use the flyback controller common in modern switching power supplies, and does not use optocoupler feedback output voltage, and the output is rectified by Schottky.
Now this charger has been very primitive, but this is also the prototype of modern switching power supply, the continuous development of portable equipment, promote people's demand for chargers, more and more new technologies applied to chargers, there has been so much progress.
The front of the circuit board is listed, from top to bottom, the input filter circuit, the filter electrolytic capacitor, the switch pipe, the transformer, and on the left side of the transformer are the output rectifier and filter capacitor.
Instead of using a single chip on the back, several transistors are used to implement the switching power supply function. The bottom of the transformer is a support silicone pad, and the primary stage is clearly demarcated.
Below we start from the input to understand the material of this charger.
Slow melt fuse at the input with a specification of 1A.
X capacitance is 0.047μF.
A close-up of the common mode inductance, limited by the material design of the year, an insulating skeleton was designed, and the core was fixed with steel sheets.
Rectifier bridge from Vishay, DF08M, rated current 1A, withstand voltage 800V.
Primary filter capacitor from Ltec Huicheng, 22μF 400V.
Switching power supply primary supply capacitor from Fongbin, 47μF 25V.
The switch tubes are from Toshiba, 2SK3567, NMOS, withstand voltage 600V, conductivity 1.7Ω, using TO220F insulated package.
Primary current sense resistor with insulated tube sleeve on pin.
Two 4007 diodes.
Transformers are tightly wound using insulating tape.
Blue Y capacitor close-up.
The rectifier is from STMIC, STPR1020CT ultra-fast recovery diode, 10A, withstand voltage 200V, available in TO220 package.
Secondary filter capacitor from TAICON, 680μF 25V.
Diodes connected in series in the output to prevent output backfilling.
All disassembled, let's take a family portrait.
Charging head net disassembly summary
After reading this charger, I feel a heavy sense of age, as a traditional old interface charger, has long been with the disappearance of the device and become electronic waste. The USB-A interface of the same period, with good versatility, has been used to this day, computers, mobile phone chargers and so on are still widely used. The USB-C interface supports high-power transmission, without distinguishing the characteristics of the front and back sides, and it is also a unified river and lake on the mobile phone.
After sighing, let's talk about this charger, the charger uses the now rare RCC circuit structure, and there is no secondary regulator loop designed, only suitable for wide voltage input FireWire devices. Considering that the output current is small, the output is rectified using an ultra-fast recovery diode. The charger is foundry by Delta, representing the mainstream manufacturing process of the year, the modern process integrates a variety of functions into a chip, and uses synchronous rectification, the power density has been greatly improved.