Phone models that support wireless charging

In fact, the entire top segment of mobile equipment from well-known manufacturers has induction current receivers. Among them are Apple, Blackerry, Sony, Yota, Kyosera, Motorola, LG, Samsung, Asus, Google, HTC, Nokia devices.

Tools and materials for making wireless charging

To make a wireless charging circuit you will need:

  • scissors or wire cutters;
  • flux and solder, in the simplest form, rosin and tin;
  • soldering iron 25-40W;
  • usual charger from a mobile phone;
  • 5V NE555 pulse shaper microcircuit;
    phone, charger
  • powerful field-effect transistor IRF-Z44;
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    An example of the arrangement of pins on an analog of a transistor

  • voltage regulator 7805; The location of the stabilizer pins
  • diode M4, for the receiver circuit;
  • capacitors. two 10n, and one 100n and 10µ;
  • resistors. 10 Ohm and 1 kOhm;
  • copper, varnished wire for the antenna. 1 mm and 0.35-0.4 mm.

Connecting elements

I would like to note that, as for any transmitting and receiving equipment, in the case of induction equipment, accuracy is also required. It will not work just to wind up the connected elements in a heap. parasitic electrical connections will arise, which will negate all the sense from the assembled device.

For the execution of the circuit, it is still recommended to etch them out of the blanks, or, if foil-coated PCB is unavailable, use a breadboard. All connections are soldered, no twists. Too unreliable and not only will there be bad contact, but also in case of its occurrence it will be difficult to find the source of the problem.

How does wireless charging for your phone work?

Unfortunately, modern models of the presented devices for transmitting current over the air have some drawbacks. But the ease of use of such equipment allows you to close your eyes to its disadvantages. Actually, the whole charging process consists in placing a mobile device nearby or on a special platform. a transmitter. Of course, a phone, tablet, Smart-watch, laptop or other end-to-end mobile device must be equipped with an appropriate client-side receiver for current through the air.

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Charging your phone over the air: one of the options

The top price segment of devices already, most likely, contains in its design a built-in receiver of induction signals of one of the common standards. Qi, PMA and AirFuel, and the corresponding transmitter can be purchased already assembled, or separately, and it also happens that it comes with mobile equipment. There are also proprietary, closed wireless charging standards, which are used, for example, by Samsung for its products.

But the main difference is not in the principle of transmission. the physical effect of electromagnetic induction is always used. but in the frequency of the alternating current at the output of the transmitter. The Qi standard, which is being developed by the concern of companies for the use of wireless energy WPC, is characterized by this parameter of emitters in the range of 100-205 kHz. PMA, produced by the company of the same name, uses the 277-357 kHz range for current transmission.

Although it lost the competition with QI, many manufacturers leave the possibility of using it in their wireless charging devices, or in a hybrid way, both standards, or specifically one PMA. Hybrid wireless charger

After the fall of PMA technology, the firm that previously produced it has joined forces with more than 200 companies belonging to the WPC concern. The result was the development of a new AirFuel standard, which implies the connection of transmitting coils, which act as antennas, at resonant frequencies, which made it possible to increase the receiving distance and the overall efficiency of the charging system.

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Transmitting current through the air

How To Make A Simple Hand-Crank Phone Charger

The question of how to wirelessly charge or transfer power to various devices over the air was asked by people more than 200 years ago. Of course, then there were no batteries, but their prototypes existed. Leyden banks. Therefore, the question of recharging them or directly supplying energy to consumer devices without using wires was also raised.

Back in the 19th century, the ancestor of all electrical physics, Andre Ampere, on whose behalf the unit for measuring current strength was named, discovered the physical phenomenon of electromagnetic induction.

His main works in this direction are related to the observation of experiments. He noticed that there is a relationship when an electromagnetic field occurs in two adjacent wire coils. If you apply current to one, then in the second one will also observe the appearance of a current at the ends of its conductors and a general magnetic effect. It was found, through experiments, that the power of electromagnetic induction drops strongly with increasing distance between the windings.

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The same Andre-Marie Ampere

DIY Phone Charger

Almost 100 years later, Ampere’s work was continued by the genius of his time, Nikola Tesla, who studied the transmission of high-frequency currents through the air and designed various devices for receiving them using this technology.

Gradually, the physical principles underlying power exchange devices over the air were forgotten and not used. The power consumption of the transmitted current is too high, the distances are small, it is difficult to manufacture receiving and transmitting equipment over long distances.

The technology got its second wind with the development of wearable gadgets and the need for their constant recharging. Batteries of mobile devices have a finite capacity, which is very small due to their size, at the same time, the internal filling of cell phones, tablets, “smart” watches and other mobile devices is becoming more and more “greedy” for consumption, which leads to the need for constant current source connections.

DIY wireless charging instructions

A fairly simple wireless charging scheme will be described. The transmitter in it is made on a timer microcircuit. a single pulse shaper and a field-effect transistor, and the receiver on a diode and a stabilizer. Wireless charging circuit

The simplicity of the design makes it possible to make it even by hanging installation. It is only necessary to remember that microcircuits and, in general, semiconductor elements do not like overheating, so the assembly must be performed holding the legs of the critical circuit components between their case and the soldering point with tweezers. This will reduce the temperature of the sensitive part. the tweezers will work like a heat sink.

It is better to use a special socket to place the timer chip on it.

DIY wireless charging

Features of the assembly and connection process

Here you need to remember that the receiver will be connected to a real, rather expensive consumer device. Therefore, before connecting, you need to check the polarity at the receiver outputs with a multimeter and the presence of the required voltage during the operation of the assembled circuit. it should be within 4-5V.

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Pointer multimeter. convenient for determining polarity

You also need to decide how to connect the consumer. There are two options here. either directly to the battery, but in this case it will not be visible whether it is already charged or not when the device is turned off, or to the standard power connector.

In both cases, the polarity and permissible currents must be checked! The cost of omission is the subsequent functionality of the mobile device.

Making the transmitter

As already mentioned, the installation of the transmitter circuit can be done both mounted and on a breadboard or self-etched board. Here, its size does not really matter. The only remark is that the antenna should be located closer to the substrate, on which the receiver is subsequently placed.

The very shape of the coil also does not have much influence on the presented circuit, but it is recommended to make it in a spiral shape, as in the photo. This will improve the characteristics of power transmission, will increase the distance between the receiver and the emitter. Transmitter with etched board and well-shaped antenna

Winding is recommended to be carried out inside a round-shaped case. for example, in a CD box. in the place where it was located. A wire is laid there, leaving the tip, to which one of the contacts of the transmitter itself will be soldered, and then the wire is laid in turns, wrapping around the previous ones. You need to make 25 such turns.

After the end of the winding, it is recommended to fill the entire structure with universal glue or epoxy resin, leaving only the final exits of the wire. Which, in turn, must be tinned, and subsequently connected to the outputs of the emitter. Emitter circuit


Given that such devices consume a lot of current, their batteries may be discharged before the moment when electricity is available from the wall outlet. If you do not want to immerse yourself in the primordial silence and spiritual STIHL, then a backup autonomous energy source can be provided for powering devices, which will help out both during a long journey into the wild, and in case of man-made or natural disasters, when your settlement may be on several days or weeks without power supply.

Diagram of a mobile charger without a 220V network

The device is a compensation-type linear voltage regulator with a low saturation voltage and a very low intrinsic current consumption. As source of energy for this stabilizer can be a simple battery, storage battery, solar or manual electric generator. The current consumed by the stabilizer when the load is off is about 0.2 mA at an input supply voltage of 6 V or 0.22 mA at a supply voltage of 9 V. The minimum difference between the input and output voltage is less than 0.2 V at a load current of 1 A! When the input supply voltage changes from 5.5 to 15 V, the output voltage changes by no more than 10 mV at a load current of 250 mA. When the load current changes from 0 to 1 A, the output voltage changes by no more than 100 mV at an input voltage of 6 V and by no more than 20 mV at an input supply voltage of 9 V.

A self-resetting fuse protects the gimbal and battery from overload. The reverse-connected diode VD1 protects the device from polarity reversal of the supply voltage. As the supply voltage increases, the output voltage also tends to increase. To keep the output voltage stable, a regulating unit assembled on VT1, VT4 is used.

A super-bright blue LED is used as a reference voltage source, which, simultaneously with performing the function of a micropower zener diode, is an indicator of the presence of an output voltage. When the output voltage tends to increase, the current through the LED increases, the current through the emitter junction VT4 also increases, and this transistor opens more strongly, and VT1 also opens more strongly. which shunts the gate-source of a powerful field-effect transistor VT3.

As a result, the on-channel resistance of the field-effect transistor increases and the voltage across the load decreases. Trimmer resistor R5 can adjust the output voltage. Capacitor C2 is designed to suppress self-excitation of the stabilizer with an increase in the load current. Capacitors C1 and SZ. blocking for power supply circuits. Transistor VT2 is included as a micropower zener diode with a stabilization voltage of 8.9 V. It is designed to protect against breakdown by high isolation voltage of the gate VT3. A gate-source voltage that is dangerous for VT3 may appear at the time of power-on or due to touching the terminals of this transistor.

Details. The KD243A diode can be replaced with any of the KD212, KD243 series. KD243, KD257, 1N4001.1N4007. Instead of KT3102G transistors, any collector similar with a low reverse current will do, for example, any of the KT3102, KT6111, SS9014, BC547, 2SC1845 series. Instead of the KT3107G transistor, any of the KT3107, KT6112, SS9015, BC556, 2SA992 series is suitable. A powerful n-channel field-effect transistor of the IRLZ44 type in a TO-220 package, has a low gate-source opening threshold voltage, a maximum operating voltage of 60 V. Maximum direct current. up to 50 A, open channel resistance 0.028 Ohm. In this design, it can be replaced by IRLZ44S, IRFL405, IRLL2705, IRLR120N, IRL530NC, IRL530N. The field-effect transistor is mounted on a heat sink with sufficient cooling surface area for a particular application. During installation, the terminals of the field-effect transistor are short-circuited with a wire jumper.

The autonomous charger can be mounted on a small printed circuit board. As an independent power source, you can use, for example, four pieces of series-connected alkaline galvanic cells with a capacity of 4 A / H (RL14, RL20). This option is preferable if you plan to use this construction relatively rarely.

If you plan to use this device relatively often or your player consumes much more current even when the display is off, then it will be advisable to use a rechargeable 6 V battery, for example, a sealed motorcycle or from a large hand lamp. You can also use a battery of 5 or 6 pieces of nickel-cadmium batteries connected in series. On a hike, on a fishing trip, to recharge batteries and power a device, it may be convenient to use a solar battery capable of delivering a current of at least 0.2 A at an output voltage of 6 V. into the “minus” circuit, therefore, simultaneous power supply of the player and, for example, a small active speaker system is possible only if both devices are connected to the output of the stabilizer.

Battery discharge indication block diagram

The zener diode must have a stabilization voltage lower than the desired LED turn-on voltage. The microcircuit used a 74HC04. Setting up the display unit consists in selecting the threshold for switching on the LED using R2. The 74NC04 microcircuit makes it so that the LED lights up when discharged to a threshold that will be set by the trimmer. The current consumption by the device is 2 mA, and the LED itself will light up only at the moment of discharge, which is convenient. I found these 74NC04 on old motherboards, that’s why I used.

To simplify the design, this discharge indicator may not be installed, because the SMD microcircuit can not be found. Therefore, the scarf is specially placed on the side and it can be cut off along the mowing line, and later, if necessary, added separately. In the future, I wanted to put an indicator on TL431 there, as a more profitable option in terms of details. The field-effect transistor stands with a margin for different loads and without a radiator, although I think it is possible to put weaker analogs, but already with a radiator.

SMD resistors are installed for Samsung devices (smartphones, tablets, etc., they have their own charging algorithm, and I do everything with a margin for the future) and they can not be installed at all. Do not put domestic KT3102 and KT3107 and their analogues, I had a voltage on these transistors because of h21. Take ВС547-ВС557, that’s it. Scheme source: Butov A. Radioconstructor. 2009. Assembly and adjustment: Igoran.

Forum for discussion of the material MOBILE CHARGER FOR TELEPHONE

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