Samsung charger pinout. Micro and mini connectors

Making your own solar USB charger for your phone is one of the most interesting and useful projects on. Make your own Charger not too complicated - the necessary components are not very expensive and are easy to obtain. Solar chargers USB devices and are ideal for charging small devices, for example, a telephone.

The weak point of all homemade solar chargers is the batteries. Most are assembled on the basis of standard nickel-metal hydride batteries - cheap, accessible and safe to use. But unfortunately NiMH batteries too much low voltage and capacity so that they can be seriously considered in quality, the energy consumption of which is only growing every year.

For example, iPhone battery 4 at 2000 mAh can still be fully recharged from a homemade solar charging with two or four AA batteries, but the iPad 2 is equipped with a 6000 mAh battery, which is no longer so easy to recharge using a similar charger.

The solution to this problem is to replace nickel-metal hydride batteries with lithium ones.

From this instruction you will learn how to make a solar panel with your own hands. USB charging with lithium battery. Firstly, compared to this, a homemade charger will cost you very little. Secondly, it is very easy to assemble. And most importantly, this lithium USB charger is safe to use.

Step 1: Required components to assemble the solar USB charger.

Electronic components:

5V or higher solar cell
3.7V Li-ion battery
Charge controller lithium ion battery
USB boost circuit direct current
Panel mount 2.5mm jack
2.5 mm jack with wire
Diode 1N4001
The wire

Construction materials:

Insulating tape
Heat shrink tubing
Double Sided Foam Tape
Solder
Tin box (or other enclosure)

Tools:

Soldering iron
Hot glue gun
Drill
Dremel (not required, but recommended)
Wire cutters
Wire stripper
Help from a friend

This tutorial shows you how to make a solar powered phone charger. You can refuse to use solar panels and limit yourself only to manufacturing regular USB charging on lithium-ion batteries.

Most of the components for this project can be purchased at online electronics stores, but the USB DC boost circuit and lithium-ion battery charge controller will not be so easy to find. Later in this guide I'll tell you where you can get most necessary components and what each of them is needed for. Based on this, you can decide for yourself which option suits you best.

Step 2: Benefits of lithium battery chargers.

You may not realize it, but most likely a lithium-ion battery is in your pocket or on your desk right now, or maybe in your wallet or... In most modern electronic devices lithium-ion batteries are used, characterized by large capacity and tension. They can be recharged many times. Most AA batteries are chemical composition are nickel-metal hydride and cannot boast of high technical characteristics.

From a chemical point of view, the difference between a standard AA NiMH battery and a Li-ion battery is chemical elements contained inside the battery. If you look at periodic table Mendeleev's elements, you will see that lithium is in the left corner next to the most chemically active elements. But nickel is located in the middle of the table next to chemically inactive elements. Lithium is so reactive because it only has one valence electron.

And it is precisely for this reason that there are many complaints about lithium - sometimes it can get out of control due to its high chemical reactivity. A few years ago Sony company, a leader in laptop batteries, produced a batch of substandard laptop batteries, some of which spontaneously ignited.

This is why when working with lithium-ion batteries, we must take certain precautions - very accurately maintain the voltage during charging. This instruction uses 3.7 V batteries, which require a charging voltage of 4.2 V. If this voltage is exceeded or decreased, the chemical reaction can get out of control with all the ensuing consequences.

That's why when working with lithium batteries extreme caution must be exercised. If you handle them carefully, they are quite safe. But if you do inappropriate things with them, it can lead to big trouble. Therefore, they should be used only strictly according to the instructions.

Step 3: Selecting a lithium-ion battery charge controller.

Due to the high chemical reactivity of lithium batteries, you must be one hundred percent sure that the charge voltage control circuit will not let you down.

Although you can make your own voltage control circuit, it is better to just buy one already ready-made diagram, in whose performance you will be confident. There are several charge control schemes available to choose from.

On this moment Adafruit is now in its second generation of charge controllers for lithium batteries with several available input voltages. These are very good controllers, but they have too much big size. It is unlikely that it will be possible to assemble a compact charger using them.

On the Internet you can buy small modules of lithium battery charging controllers, which are used in this manual. Based on these controllers, I also assembled many others. I like them for their compactness, simplicity and availability LED indication battery charge. As with Adafruit, when there is no sun, the lithium battery can be charged via the controller's USB port. The ability to charge via USB port is extremely useful option for any solar charger.

Regardless of which controller you choose, you should know how it works and how to operate it correctly.

Step 4: USB port.

The USB port can charge most modern devices. This is the standard all over the world. Why not just connect the USB port directly to the battery? Why do you need a special circuit for charging via USB?

The problem is that according to USB standard the voltage is 5V and the lithium ion batteries we will use in this project, have a voltage of only 3.7 V. Therefore, we will have to use a USB DC boost circuit, which increases the voltage enough to charge various devices. Most commercial and homemade USB chargers, on the contrary, use step-down circuits, since they are assembled on the basis of 6 and 9 V batteries. Step-down circuits are more complex, so it is better not to use them in solar chargers.

The circuit used in this manual was selected as a result of extensive testing. various options. It's almost identical to Adafruit's Miniboost circuit, but costs less.

Of course you can buy an inexpensive USB charger online and take it apart, but we need a circuit that converts 3V (the voltage of two AA batteries) to 5V (the voltage on the USB). Disassembling a regular or car USB charger will not do anything, since their circuits work to reduce the voltage, but on the contrary, we need to increase the voltage.

In addition, it should be noted that the Mintyboost circuit and the circuit used in the project are capable of working with Apple gadgets, unlike most other USB charging devices. Apple devices check the information pins on the USB to know where they are connected. If Apple gadget determines that the information pins do not work, then it will refuse to charge. Most other gadgets do not have such a check. Believe me - I tried many cheap charging circuits from eBay - none of them managed to charge my iPhone. You don't want your homemade USB The charger could not charge Apple gadgets.

Step 5: Battery selection.

If you Google a little, you'll find a huge different sizes, capacities, voltages and costs. At first, it will be easy to get confused in all this diversity.

For our charger, we will use a 3.7V lithium polymer (Li-Po) battery, which is very similar to an iPod or cell phone battery. Indeed, we only need a 3.7 V battery, since the charging circuit is designed for this voltage.

The fact that the battery should be equipped with built-in protection against overcharge and overdischarge is not even discussed. This protection is usually called "PCB protection". Search these keywords on the online auction eBay. She is just a small printed circuit board with a chip that protects the battery from overcharging and discharging.

When choosing a lithium-ion battery, look not only at its capacity, but also at its physical size, which mainly depends on the case you choose. I used an Altoids tin box as the case, so I was limited in my choice of battery. At first I thought of buying a 4400 mAh battery, but because of it large sizes I had to limit myself to a 2000 mAh battery.

Step 6: Connecting the solar panel.

If you are not going to make a charger that can be recharged from the sun, you can skip this step.

This tutorial uses a solar panel in hard plastic case at 5.5 V and 320 mA. Any large solar panel will work for you. For the charger, it is best to choose a battery designed for a voltage of 5 - 6 V.

Take the wire by the end, divide it into two parts and strip the ends a little. A wire with a white stripe is negative, and an all-black wire is positive.

Solder the wires to the corresponding contacts on the reverse side solar battery.

Cover the solder joints with electrical tape or hot glue. This will protect them and help reduce stress on the wires.

Step 7: Drill the tin box or housing.

Since I used an Altoids tin as the body, I had to do a little drill work. In addition to the drill, we will also need a tool such as a dremel.

Before you start working with a tin box, put all the components in it to make sure in practice that it suits you. Think about how best to place the components in it, and only then drill. You can mark the locations of the components with a marker.

After designating the places, you can get to work.

There are several ways to remove the USB port: make a small cut right at the top of the box, or drill a hole of the appropriate size on the side of the box. I decided to make a hole on the side.

First, attach the USB port to the box and mark its location. Drill two or more holes inside the designated area.

Sand the hole with the Dremel. Be sure to follow safety precautions to avoid injuring your fingers. Do not hold the box in your hands under any circumstances - clamp it in a vice.

Drill a 2.5mm hole for the USB port. If necessary, widen it using a Dremel. If you don't plan to install a solar panel, then the 2.5mm hole is not necessary!

Step 8: Connecting the charging controller.

One of the reasons I chose this compact charge controller is its reliability. He has four contact pads: two in front next to the mini-USB port, where constant pressure(in our case from solar panels), and two at the back for the battery.

To connect a 2.5 mm connector to the charging controller, you need to solder two wires and a diode from the connector to the controller. In addition, it is advisable to use heat-shrinkable tubing.

Fix the 1N4001 diode, charge controller and 2.5mm jack. Place the connector in front of you. If you look at it from left to right, the left contact will be negative, the middle one will be positive, and the right one is not used at all.

Solder one end of the wire to the negative leg of the connector, and the other to the negative pin on the board. In addition, it is advisable to use heat-shrinkable tubing.

Solder another wire to the diode leg, next to which there is a mark. Solder it as close to the base of the diode as possible to save more free space. Solder the other side of the diode (without the mark) to the middle pin of the connector. Again, try to solder as close to the base of the diode as possible. Finally, solder the wires to the positive contact on the board. In addition, it is advisable to use heat-shrinkable tubing.

Step 9: Connecting the battery and USB circuit.

On at this stage You just need to solder four additional pins.

You need to connect the battery and USB circuit to the charge controller board.

First cut some wires. Solder them to the positive and negative terminals on USB circuit, which are located on bottom side fees.

After that, connect these wires together with the wires coming from the lithium-ion battery. Make sure you connect the negative wires together and connect the positive wires together. Let me remind you that the red wires are positive and the black wires are negative.

Once you have twisted the wires together, weld them to the terminals on the battery that are on back side charging controller boards. Before soldering, it is advisable to thread the wires into the holes.

Now we can congratulate you - you have completed the task 100% electrical part this project and you can relax a little.

At this stage, it is a good idea to check the functionality of the circuit. Since all electrical components are connected, everything should work. Try charging your iPod or any other gadget equipped with a USB port. The device will not charge if the battery is low or defective. In addition, place the charger in the sun and see if the battery will charge from the solar panel - the small red LED on the charge controller board should light up. You can also charge the battery via a mini-USB cable.

Step 10: Electrically isolate all components.

Before placing all the electronic components in the tin box, we must be sure that it cannot cause short circuit. If you have a plastic or wooden case, then skip this step.

Place several strips of electrical tape on the bottom and sides of the tin box. It is in these places that the USB circuit and charging controller will be located. The photos show that my charging controller was left loose.

Try to carefully insulate everything so that a short circuit does not occur. Make sure the solder joints are secure before applying hot glue or tape.

Step 11: Placing the Electronic Components in the Case.

Since the 2.5mm jack needs to be secured with bolts, place it first.

My USB circuit had a switch on the side. If you have the same circuit, then first check whether the switch that is needed to turn the “charging mode” on and off works.

Finally, you need to secure the battery. For this purpose, it is better to use not hot glue, but several pieces of double-sided tape or electrical tape.

Step 12: Operate your homemade solar charger.

Finally, let's talk about correct operation homemade USB charging.

You can charge the battery via a mini-USB port or from the sun. The red LED on the charge controller board indicates the charging process, and the blue LED indicates a fully charged battery.

Converting a car charger to charge from a 12 volt battery

5 Volt">Simple 12→5 volt converter circuits using voltage stabilizers

All materials on the topic
All materials on the topic
All materials on the topic
________________________________
Majority modern gadgets (mobile phones, smartphones, players, e-books, etc.) supports charging via a USB mini/micro socket. There may be several connection options:

The device can be charged from a PC via a standard data cable. Usually this is a USB_AM—USB_BM_mini/micro cable. If a device requires a current of more than 0.5 A to charge (this is the maximum that USB 2.0 is capable of), then the charging time can be painfully long, even indefinitely. The USB 3.0 port (the blue one) already produces 0.9 A, but this may not seem enough to some.

Using the same data cable, your device can be charged from native charger (mains or car) equipped with a 4-pin USB-AF socket, like on a computer. Of course, this is no longer a real USB port. The charger socket only outputs approximately 5V between pins 1 and 4 of the 4-pin socket (plus on pin #1, minus on pin #4). Well, still in between different contacts All kinds of jumpers and resistors can be installed in the sockets. For what? This witchcraft will be discussed below.

The gadget can be connected to a third-party or homemade charger that provides 5 volts. And this is where the fun begins...

When you try to charge from someone else's charger with a USB output, your gadget may refuse to charge under the pretext that the charger is supposedly not suitable for it. The answer is that many phones/smartphones “look” at how the Data+ and Data- wires are connected, and if the gadget doesn’t like something, the charger will be rejected.

Nokia, Philips, LG, Samsung, HTC and many other phones will only recognize the charger if the Data+ and Data- pins (2nd and 3rd) are shorted. You can short them in the USB_AF socket of the charger and easily charge your phone via a standard data cable.

If the charger already has an output cord (instead of an output jack), and you need to solder a mini/micro USB plug to it, then do not forget to connect pins 2 and 3 in the mini/micro USB itself. In this case, you solder the plus to 1 contact, and the minus to the 5th (last).

U iPhones In general, there are some occult requirements for switching the charger socket: the Data+ (2) and Data- (3) contacts must be connected to the GND contact (4) through 49.9 kΩ resistors, and to the +5V contact through 75 kΩ resistors.

Motorola“requires” a 200 kOhm resistor between pins 4 and 5 USB plug micro-BM. Without a resistor, the device does not charge until it is completely charged.

To charge Samsung Galaxy The USB micro-BM plug must have a 200 kOhm resistor between pins 4 and 5 and a jumper between pins 2 and 3.

For a more complete and “humane” charge of the tablet Samsung Galaxy Tab recommend another circuit: two resistors: 33 kOhm between +5 and jumper D-D+; 10 kOhm between GND and jumper D-D+.

Apparatus E-ten(“Raccoon”) is not interested in the state of these contacts, and will support even a simple charger. But he has an interesting requirement for charging cable— “Raccoon” charges only if pins 4 and 5 are short-circuited in the mini-USB plug.

If you don’t want to bother with a soldering iron, you can buy a USB-OTG cable - in its mini-USB plug, pins 4 and 5 are already closed. But then you will still need USB adapter AM-AM, that is, “dad” - “dad”.

The Ginzzu GR-4415U car charger and its analogues, which claim to be universal, are equipped with two output sockets: “HTC/Samsung” and “Apple” or “iPhone”. The pinout of these sockets is shown below.

For power or charge Garmin navigator A special data cable is required. Just to power the navigator via a data cable, you need to short-circuit pins 4 and 5 of the mini-USB plug. To recharge, you need to connect pins 4 and 5 through an 18 kOhm resistor:

Separate topic - charging tablets. As a rule, a tablet requires a decent current (1÷1.5 amperes) to charge, and charging through the mini/micro-USB socket in many tablets is simply not provided by the manufacturer. After all, even USB 3.0 will not provide more than 0.9 amperes.
True, some tablet models can be charged slowly and sadly when turned off.
On YouTube, one guy suggests installing a jumper in the 3Q tablet between the first contact of the mini/micro-USB socket (this is +5 V) and the positive (central) contact of the round (coaxial) charging socket. They say that this tablet has enough current from USB, it’s just that the + USB socket is not connected to the battery charge controller. After installing the jumper, the tablet supposedly charges. In principle, this is a solution if the round charging socket itself is already broken.
On the contrary, if the round socket is fine, but for some reason you want to take power for charging from Computer USB or a charger with such a connector, you can make the following adapter:

True, it has nothing to do with the topic of this article.

________________________________________ ________________________________________ __________________

So, if you want to convert a regular charger into a USB charger for your phone:

make sure the device produces about 5 volts DC voltage

find out if this charger is capable of delivering a current of at least 500 mA

make the necessary changes to the connection of the USB-AF socket or USB-mini/micro plug

Sent by:

Victor Pankov sent interesting link to an article that describes in detail the features USB pinouts connectors for correct charging of various gadgets, because it’s no secret that gadgets often refuse to charge from simple USB drive or computer port, or do not behave as expected.

Most modern gadgets (mobile phones, smartphones, players, e-readers, tablets, etc.) support charging via a USB mini/micro socket. There may be several connection options:

The device can be charged from a PC via a standard data cable. Usually this is a USB_AM-USB_BM_mini/micro cable. If a device requires a current of more than 0.5 A to charge (this is the maximum that USB 2.0 is capable of), then the charging time can be painfully long, even indefinitely. The USB 3.0 port (the blue one) already produces 0.9 A, but this may not seem enough to some.

Using the same data cable, your device can be charged from a native charger (mains or car) equipped with a 4-pin USB-AF socket, like on a computer. Of course, this is no longer a real USB port. The charger socket only outputs approximately 5V between pins 1 and 4 of the 4-pin socket (plus on pin #1, minus on pin #4). Well, all sorts of jumpers and resistors can be installed between different contacts of the socket. For what? This witchcraft will be discussed below.

The gadget can be connected to a third-party or homemade charger that provides 5 volts. And this is where the fun begins...

Motorola“requires” a 200 kOhm resistor between pins 4 and 5 of the USB micro-BM plug. Without a resistor, the device does not charge until it is completely charged.

To charge Samsung Galaxy The USB micro-BM plug must have a 200 kOhm resistor between pins 4 and 5 and a jumper between pins 2 and 3.

For a more complete and “humane” charge of the tablet Samsung Galaxy Tab They recommend another circuit: two resistors: 33 kOhm between +5 and the D-D+ jumper; 10 kOhm between GND and jumper D-D+.

Apparatus E-ten(“Raccoon”) is not interested in the state of these contacts, and will support even a simple charger. But it has an interesting requirement for the charging cable - “Raccoon” charges only if pins 4 and 5 are short-circuited in the mini-USB plug.

If you don't want to bother with a soldering iron, you can buy USB-OTG cable- in his mini-USB plug, contacts 4 and 5 are already closed. But then you will also need a USB AM-AM adapter, that is, “male”-“male”.

A special data cable is required to power or charge your Garmin navigator. Just to power the navigator via a data cable, you need to short-circuit pins 4 and 5 of the mini-USB plug. To recharge, you need to connect pins 4 and 5 through an 18 kOhm resistor:

So, if you want to convert a regular charger into a USB charger for your phone:

Make sure the device produces approximately 5 volts DC voltage

Find out if this charger is capable of delivering a current of at least 500 mA

Make any necessary changes to the USB-AF jack or USB-mini/micro plug connections

Hello Habra gentlemen and Habra ladies!
I think some of you are familiar with the situation:
“Car, traffic jam, Nth hour behind the wheel. The communicator with the navigator running has been beeping for the third time about the end of the charge, despite the fact that it is always connected to charging. And you, as luck would have it, have absolutely no bearings in this part of the city.”
Next, I will talk about how, with moderately straight hands, a small set of tools and a little money, you can build a universal one (suitable for charging with a rated current of both Apple and all other devices), car USB charging for your gadgets.

CAUTION: Under the cut there are a lot of photos, a little work, no LUT and no happy ending (not yet).

Author, why all this?

Some time ago, the story described in the prologue happened to me, a Chinese USB twin absolutely shamelessly let my smart device run out of charge while navigating; out of the declared 500mA, it produced about 350 on both sockets. I must say I was very angry. Well, okay - I’m a fool, I decided, and on the same day, in the evening, I ordered a 2A car charger on eBay, which rested in the depths of the Chinese-Israeli post office. By luck, I had a handkerchief DC-DC step down converter with an output current of up to 3 A lying around and I decided to use it to build myself a reliable and universal car charger.

A little about chargers.
I would divide most chargers that are on the market into four types:
1. Apple - tailored for Apple devices, equipped with a little charging trick.
2. Ordinary - aimed at most gadgets for which shorted DATA+ and DATA- are enough for consumption rated current charge (the one stated on the charger of your gadget).
3. Clueless - for whom DATA+ and DATA- are hanging in the air. In this regard, your device decides that it is a USB hub or a computer and does not consume more than 500 mA, which negatively affects the charging speed or even the absence of it under load.
4. Cunning%!$&e - since they have a microcontroller installed inside, which tells the device something like what Kipling’s well-known hero told animals - “You and I are of the same blood, you and I”, checks the originality of the charge. For all other devices they are memory devices of the third type.

For obvious reasons, I consider the last two options uninteresting and even harmful, so let’s focus on the first two. Since our charger must be able to charge both Apple and all other gadgets, we use two USB output, one will be focused on Apple devices, the second on all others. I will only note that if you mistakenly connect the gadget to a USB socket that is not intended for it, nothing bad will happen, it will just take the same notorious 500mA.
So, the goal: “With a little work with your hands, get a universal charger for the car.”

What do we need

1. First, let’s look at the charging current, usually it’s 1A for smartphones and about 2 Amps for tablets (by the way, my Nexus 7, for some reason it doesn’t take more than 1.2A from its own charge). In total, to simultaneously charge a medium-sized tablet and smartphone, we need a current of 3A. So the DC-DC converter that I have in stock is quite suitable. I must admit that a 4A or 5A converter would be better suited for these purposes, so that the current would be enough for 2 tablets, but I never found compact and inexpensive solutions, and besides, time was running out.
So I used what I had:
Input voltage: 4-35V.
Output voltage: 1.23-30V (adjustable by potentiometer).
Maximum output current: 3A.
Type: Step Down Buck converter.

2. USB socket, I used a double one, which I unsoldered from an old USB hub.

You can also use regular sockets from a USB extension cable.

3. Development board. In order to solder a USB socket to something and assemble a simple charging circuit for Apple.

4. Resistors or resistors, whichever you prefer, and one LED. There are 5 pieces in total, 75 kOhm, 43 kOhm, 2 rated 50 kOhm and one rated at 70 Ohm. The first 4 are exactly where the Apple charging circuit is built; I used 70 Ohms to limit the current on the LED.

5. Body. I found a case for a Mag-Lite flashlight in the bins of my homeland. In general, a black toothbrush case would be ideal, but I couldn’t find one.

6. Soldering iron, rosin, solder, wire cutters, drill and an hour of free time.

Assembling the charger

1. First of all, I short-circuited the DATA+ and DATA- pins on one of the sockets:

*I apologize for the harshness, I got up early and my body wanted to sleep, but my brain wanted to continue the experiment.

This will be our outlet for non-Apple gadgets.

2. We cut off the size of the breadboard we need and mark and drill holes in it for the mounting legs of the USB socket, while simultaneously checking that the contact legs coincide with the holes in the board.

3. Insert the socket, fix it and solder it to the breadboard. We connect the +5V contacts of the first (1) and second (5) sockets to each other, and do the same with the GND contacts (4 and 8).

The photo is for clarification only, the contacts are soldered already on the breadboard

4. Solder the following circuit to the remaining two contacts DATA+ and DATA-:

To maintain polarity, we use the USB pinout:

I got it like this:

Don’t forget to adjust the output voltage; use a screwdriver and a voltmeter to set it to 5 - 5.1V.

I also decided to add an indication to the circuit USB power supply, in parallel to +5V and GND I soldered yellow ice with a 70 Ohm resistor to limit the current.

A convincing request to people with a fine mental organization and other lovers of beauty: “Do not look at the following picture, because the soldering is crooked.”

I'm brave!

5. We fix the converter board on our breadboard. I did this using the legs from the same resistors, soldering them into the contact holes on the converter board and on the breadboard.

6. Solder the outputs of the converter to the corresponding inputs on the USB socket. Maintain polarity!

7. Take the case, mark and drill holes for mounting our board, mark and cut out a place for a USB socket and add holes for ventilation opposite the converter chip.

Fastening breadboard bolts to the body and we get this box:

In the Machine it looks like this:

Tests

Next, I decided to check whether my devices would actually consider that they were being charged from native charging. And at the same time measure the currents.
Power is provided by a power supply from an old 24V 3.3A printer.
I measured the current before outputting to USB.

Looking ahead, I’ll say that all the devices I have recognized charging.
To USB outlet number one (which is for different gadgets) I connected:
HTC Sensation, HTC Wildfire S, Nokia E72, Nexus 7, Samsung Galaxy ACE2.
For the Sensation and Nexus 7, I checked the charging time, starting at 1% and charging up to 100%.
The smartphone charged in 1 hour 43 minutes (Anker 1900 mAh battery), I should note that it takes about 2 hours to charge on a standard charge.
The tablet charged in 3 hours 33 minutes, which is half an hour longer than charging from the mains (I only charged one device at a time).

So that both Android devices They took the maximum from the charger, I had to solder a small adapter (which connected to apple USB), the HTC Sensation was connected to it.

I connected to USB socket number two: Ipod Nano, iPod touch 4G, Iphone 4S, iPad 2. Since it’s ridiculous to charge Nano with such a thing, it took a maximum of 200 mA from me, tested Touch 4g and iPad. The iPod was charged in 1 hour and 17 minutes from zero to 100% (albeit together with the IPAD 2). The iPad 2 took 4 hours and 46 minutes to charge (one).

As you can see, the iPhone 4S happily consumes its rated current.

By the way, Ipad 2 surprised me; it absolutely did not shy away from a circuit with short-circuited data contacts and consumed exactly the same currents as from the socket intended for it.

Charging process and conclusions

To begin with, let me remind you that all devices that use lithium batteries have a charge controller. It works according to the following scheme:

The graph is average and may vary for different devices.

As can be seen from the graph, at the beginning of the charging cycle, the controller allows you to charge with the maximum permissible current for your device and gradually reduces the current. The charge level is determined by voltage; the controllers also monitor the temperature and turn off charging at high temperatures. Charge controllers can be located in the device itself, in the battery or in the charger (very rarely).
You can read more about charging lithium cells.

Actually, here we come to the point why this topic is called: “Attempt number one.” The fact is that the maximum that I was able to squeeze out of charging is: 1.77A

Well, the reason, in my opinion, is not the optimally selected inductor, which in turn does not allow the Buck converter to produce its maximum current. I thought about replacing it, but I don’t have a tool for SMD soldering and don’t have any plans to do so in the near future. This is not a mistake of the designers of the board from ebay, it is simply a feature of this circuit since it is oriented to different incoming and outgoing voltages. Under such conditions, it is simply impossible to produce the maximum current over the entire voltage range.

As a result, I got a device that is capable of charging two smartphones at the same time or one tablet in a car in a reasonable amount of time.

In connection with the above, it was decided to leave this charger as is and assemble a new one, completely with our own hands, based on a more powerful LM2678 converter,
which in the future will be able to “feed” two tablets and a smartphone at the same time (5A output). But more on that next time!

Android.

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Problems with USB charging usually appear when used a foreign (non-original) charger. The gadget may charge slowly, not fully, or may even refuse to charge at all. Actually, this article is devoted to this problem. But first I have to say a few things important comments Regarding USB charging in general.

Oddly enough, some mobile devicesDoesn't support USB charging at all mini/micro, although they are equipped with it. For example, some tablets are equipped with a separate (round) socket for connecting charger (memory).
When charging a device from a USB computer, you should understand that USB port capable of delivering a current of no more than 0.5 amperes () or no more than 0.9 amperes (). And if a higher current (1÷2 amperes) is required to charge the device, then the charging time can be painfully long, even indefinitely. You will have to look for a charger of suitable power.
To understand which contacts are responsible for what in general USB connectors and how they are numbered, read the article “”. In short: the first pin in USB is +5 volts, and the last is ground.

The practical side of the issue is that the gadget sees the voltages it needs on pins 2 and 3, and this is ensured by connecting various resistances between the pins of the USB charger. At the end of the article there is a drawing of various types of charging ports (without reference to gadget models) indicating the voltages on pins 2 and 3. It also indicates what resistances this can be achieved. And right now we'll see what they're waiting for certain models gadgets from the charger port.

Nokia, Fly, Philips, LG, Explay, Dell Venue and many other devices will recognize the charger only if the Data+ and Data- pins (2nd and 3rd) are shorted or shorted with a resistor of no more than 200 Ohms ▼
You can short-circuit pins 2 and 3 in the USB_AF socket of the charger and easily charge your phone via a standard data cable. The Freelander PD10 Typhoon tablet supports the same scheme, but in addition it requires increased voltage charge, namely 5.3 volts.
If the charger already has an output cord (instead of an output jack), and you need to solder a mini/micro USB plug to it, then do not forget to connect pins 2 and 3 in the mini/micro USB itself. In this case, you solder the plus to 1 contact, and the minus to the 5th (last). ▼

HTC and others " Koreans": one resistor 30 kOhm between +5 and jumper D-D+; another resistor 10 kOhm between GND and jumper D-D+ ▼

iPhone and other products " Apple" The tablet is readily charged from the same port Freelander PX1. ▼

A car charger that claims to be universal " Ginzzu GR-4415U" and its analogues are equipped with two output sockets: "" and " Apple" or "iPhone". The pinout of these sockets is shown below. ▼

Old Motorola"requires" a resistor 200 kOhm between pins 4 and 5 of the USB micro-BM plug. Without a resistor, the device does not charge until it is completely charged. ▼

Apparatus E-ten(“Raccoon”) is not interested in the state of these contacts, and will support even a simple charger. But it has an interesting requirement for the charging cable - the “Raccoon” charges only if pins 4 and 5 are short-circuited in the mini-USB plug. ▼

Separate topic - charging tablets. As a rule, a tablet requires a decent current (1÷1.5 amperes) to charge, and charging through the mini/micro-USB socket in many tablets is simply not provided by the manufacturer. After all, even USB 3.0 will not provide more than 0.9 amperes.
True, some tablet models can be charged slowly and sadly when turned off.
On YouTube, one guy suggests installing a jumper in the 3Q tablet between the first contact of the mini/micro-USB socket (this is +5 V) and the positive (central) contact of the round (coaxial) charging socket. They say that this tablet has enough current from USB, it’s just that the + USB socket is not connected to the battery charge controller. After installing the jumper, the tablet supposedly charges. In principle, this is a solution if the round charging socket itself is already broken.
On the contrary, if the round socket is ok, but for some reason you want to take power for charging from a USB computer or charger with such a connector, then you can make such an adapter. ▼

True, it has nothing to do with the topic of this article.

I repeat, detailed information can be found in the article. Here I will give a summary diagram of the voltages on USB contacts indicating the values of resistors that allow certain voltages to be obtained. Where a resistance of 200 Ohms is indicated, you need to install a jumper, the resistance of which should not exceed those same 200 Ohms.

The diagram is clickable ▼

So, if you want to convert a regular charger into a USB charger for your phone:

make sure the device produces about 5 volts DC voltage
find out if this charger is capable of delivering a current of at least 500 mA
make the necessary changes to the connection of the USB-AF socket or USB-mini/micro plug

Related materials:

for charging from a 12 volt battery
volts on voltage stabilizers

All materials on the topic
All materials on the topic