Basic circuits of pulse network adapters for charging phones. Portable phone charger from one battery Charger switching and identification unit

In this article I will provide a portable charging circuit for a mobile phone. Such chargers appeared on the market recently, but have already managed to win the hearts of tourists and hikers. Today in stores you can see a huge number of similar chargers of various types. We will look at the design of a homemade field charger, which is powered by just one AA battery. This charging is very convenient, does not take up much space, and most importantly, it is powered by one battery, which can be found in any counter.

The design is a step-up DC-DC voltage converter, the output of which produces a voltage of 5.6 Volts. The rated output current is 180-220mA - these parameters are sufficient to charge any mobile phone, player or receiver.

The circuit is simple and works even with a wide range of components used. Therefore, such a portable phone charger is available to absolutely everyone.

Cumulative choke - in my case, it was taken ready-made, it consists of 10 turns of copper wire with a diameter of 0.5 mm (0.3-0.6 mm).

Transistors are not critical. You can use both domestic and imported transistors. KT814 can be replaced with transistors - KT816 or low-power ones - KT361, KT3102. D1760 was selected through experiments, but it can be successfully replaced with KT817, KT815, you can also use more powerful low-frequency transistors such as KT819, KT805 and even composite KT829, etc.

Literally any domestic or imported zener diode is suitable as a zener diode. You can install zener diodes like BZV85C5V6, 1N4734A or any others with a stabilization voltage of 5-6 Volts.

Any Schottky diode is suitable as a rectifier, but experience shows that a rectifier is not needed if there is an electrolyte at the output. The voltage of the electrolytic capacitor is selected in the region of 10-25 Volts, there is no point anymore.

In my case, such a portable charger has been used for a long time for the NOKIA N95 smartphone. The main advantage of charging is that the circuit works even when the input voltage is about 0.8-1 Volt (factory circuits stop working when the input voltage is below 1.4 Volt). Thus, to power this circuit, you can use nickel-cadmium or nickel-metal hybrid batteries with a voltage of 1.2 Volts. I would like to remind you that factory chargers will not work at this voltage, but our circuit works very well. This concludes our next article.

Until we meet again - AKA KASYAN.

A. A smartphone is a device that has become an indispensable communication device for all people. They are used to access the Internet and often for a long time. But smartphones have one drawback - battery life. In the best case, the battery will work without recharging for one day, and if you use it actively, then for several hours. This article and accompanying video show you how to make a powerful homemade Powerbank that can even charge your smartphone or tablet or a combination of both simultaneously.

You can buy the baby monitor, which is described at the beginning of the video, and all the components of the power bank in this Chinese store. Information on how to receive cashback (refund) in the amount of 7% of the price of all purchases is on our website. Download the schematic, board and other project files.

In order to improve the performance of mobile phone batteries, portable chargers were ordered, which are popularly called power banks. But in its single form, such a device is not even half capable of charging a phone battery. And even three such devices do not provide a way out of the situation. Buying a powerful power bank is quite expensive. A normal powerbank, say, with a capacity of 10,000 milliamps costs 25-30 dollars. Considering this and the long waiting time for the parcel, it is easier to make your own option.

Description of the power bank circuit

The powerbank circuit consists of three main parts. This is a lithium battery charge controller with an auto-shutoff function when fully charged; battery compartment with parallel-connected 18650 lithium-ion batteries; 5-10 amp power switch from the computer power supply; a boost converter in order to increase the voltage from the battery to the desired values ​​of 5 volts, which are needed to charge a phone or tablet; USB connector to which the device to be charged is connected.

In addition to its simplicity and low cost, the presented circuit has high output current values, which can reach up to 4 amperes and depends on the rating of components such as a field-effect transistor, a Schottky diode at the output and inductance. Chinese analogues are capable of providing an output current of no more than 2.1 amperes. This is enough to charge a couple of smartphones at the same time, and our power bank can handle 4-5 smartphones.

Let's look at the individual components of the structure. The power source is 5 parallel-connected 18650 batteries from a laptop. The capacity of each battery is 2600 milliamps per hour. The housing used is from an adapter or inverter, but another suitable housing can be used. We will use a charging board purchased as a charge controller. The charging current is about 1 ampere. You can also take a ready-made inverter that will increase the voltage from the battery to the required 5 volts. It's very cheap. Maximum output current up to 2 amperes.

Circuit assembly

At the first stage, we fix the batteries and fasten them together using a glue gun. Next, you need to connect the controller to the battery to check how the charging process occurs. You also need to find out the battery charge time and understand whether auto-shutdown works when fully charged. Everything is labeled in detail on the board.

You can charge from any USB port. The indicator should show that charging is in progress. After 5 hours, the second indicator lights up, which means the charging process is complete. If a metal case is used, the batteries should be additionally insulated using wide tape.

One of the main components of the circuit is a step-up dc-dc converter, an inverter - voltage converter. It is designed to raise the voltage from the batteries to 5 Volts needed to charge the phone. The voltage of one battery is 3.7 volts. Here they are connected in parallel, so an inverter is needed.

The system is built on a 555 timer - a field-effect transistor and stabilization of the output voltage, which is set using a zener diode vd2. You may have to pick up a zener diode. Any low-power zener diode will do. Resistors of 0.25 or even 0.125 watts. Inductor L1 can be removed from the computer power supply. The diameter of the wire is at least 0.8, it is best to make 1 millimeter. The number of turns is 10-15.

The circuit contains a frequency-setting unit that sets the operating frequency of the timer. The latter is connected as a square pulse generator. With this selection of components, the operating frequency of the timer is about 48-50 kHz. Gate limiting resistor R3 for a 4.7 Ohm field effect transistor. Resistance can be from 1 to 10 Ohms. You can replace this resistor with a jumper. Field effect transistor of any average power with a current of 7 amperes. Field switches from motherboards are suitable. Small reverse conduction transistor vt1. A kt315 or other low-power reverse conduction transistor will do. Rectifier diode - it is advisable to use a Schottky diode with a minimum voltage drop across the junction. Two containers serve as a power filter.

This inverter is pulsed, it provides high efficiency, high output voltage stabilization, and does not heat up during operation. Therefore, there is no need to install power components on the heat sink. If there are difficulties with Schottky diodes, then you can use the diodes that are in computer power supplies. Dual to-220 diodes are found in them.

The photo below shows the inverter in assembled condition.

You can make a printed circuit board. There is a link in the description.

Testing a 5 volt inverter

We check the inverter for functionality. The smartphone is charging, as you can see, the charging process is in progress. The output voltage is kept at 5.3 volts, which fully complies with the standards. The inverter does not heat up.

Final assembly into the body

We need to cut out the side walls from a piece of plastic. The charge controller has two LED indicators that show the charge percentage. They need to be replaced with brighter ones and displayed on the front panel. There are two holes cut out in the side wall for micro USB connectors, which means you can charge two devices at the same time. There are also holes for LEDs. A hole for the controller, that is, for charging the built-in batteries. A small hole will also be made for the power switch.

All connectors, LEDs and switch are fixed with a glue gun. All that remains is to pack everything into the case.

A USB tester is connected to the output of the device. It can be seen that the output voltage remains firmly at 5 volts. Let's connect mobile phones and try to charge them from a homemade Power bank. Two smartphones will be charged at once. The charging current jumps to 1.2 Amperes, the voltage is also normal. The charging process is progressing successfully. The inverter works flawlessly. It turned out compact and, most importantly, stable. The circuit is easy to assemble; familiar components are used.

The number of mobile communications devices in active use is constantly growing. Each of them comes with a charger supplied in the kit. However, not all products meet the deadlines set by the manufacturers. The main reasons are the low quality of electrical networks and the devices themselves. They often break down and it is not always possible to quickly purchase a replacement. In such cases, you need a circuit diagram for a phone charger, using which it is quite possible to repair a faulty device or make a new one yourself.

Main faults of chargers

The charger is considered the weakest link in mobile phones. They often fail due to poor quality parts, unstable mains voltage or as a result of ordinary mechanical damage.

The simplest and best option is to purchase a new device. Despite the differences in manufacturers, the general schemes are very similar to each other. At its core, this is a standard blocking generator that rectifies the current using a transformer. Chargers may differ in connector configuration, they may have different circuits of input network rectifiers, made in a bridge or half-wave version. There are differences in small things that are not of decisive importance.

As practice shows, the main faults of the memory are the following:

• Breakdown of the capacitor installed behind the mains rectifier. As a result of the breakdown, not only the rectifier itself is damaged, but also a constant resistor with low resistance, which simply burns out. In such situations, the resistor practically acts as a fuse.
• Transistor failure. As a rule, many circuits use high-voltage high-power elements marked 13001 or 13003. For repairs, you can use the domestically produced KT940A product.
• Generation does not start due to a breakdown of the capacitor. The output voltage becomes unstable when the zener diode is damaged.

Almost all charger housings are non-separable. Therefore, in many cases, repairs become impractical and ineffective. It is much easier to use a ready-made DC source by connecting it to the required cable and supplementing it with the missing elements.

Simple electronic circuit

The basis of many modern chargers are the simplest pulse circuits of blocking generators, containing only one high-voltage transistor. They are compact in size and capable of delivering the required power. These devices are completely safe to use, since any malfunction leads to a complete absence of voltage at the output. This prevents high unstabilized voltage from entering the load.

The rectification of the alternating voltage of the network is carried out by the diode VD1. Some circuits include an entire diode bridge of 4 elements. The current pulse is limited at the moment of switching on by resistor R1 with a power of 0.25 W. In case of overload, it simply burns out, protecting the entire circuit from failure.

To assemble the converter, a conventional flyback circuit based on transistor VT1 is used. More stable operation is ensured by resistor R2, which starts generation at the moment of power supply. Additional generation support comes from capacitor C1. Resistor R3 limits the base current during overloads and power surges.

High reliability circuit

In this case, the input voltage is rectified by using a diode bridge VD1, a capacitor C1 and a resistor with a power of at least 0.5 W. Otherwise, while charging the capacitor when turning on the device, it may burn out.

Capacitor C1 must have a capacity in microfarads equal to the power of the entire charger in watts. The basic circuit of the converter is the same as in the previous version, with transistor VT1. To limit the current, an emitter with a current sensor based on resistor R4, diode VD3 and transistor VT2 is used.

This phone charger circuit is not much more complicated than the previous one, but much more efficient. The inverter can operate stably without any restrictions despite short circuits and loads. Transistor VT1 is protected from emissions of self-induction EMF by a special chain consisting of elements VD4, C5, R6.

It is necessary to install only a high-frequency diode, otherwise the circuit will not work at all. This chain can be installed in any similar circuits. Due to this, the housing of the switch transistor heats up much less, and the service life of the entire converter increases significantly.

The output voltage is stabilized by a special element - a zener diode DA1, installed at the charging output. Optocoupler V01 is used.

DIY charger repair

With some knowledge of electrical engineering and practical skills in working with tools, you can try to repair a cell phone charger on your own.

First of all, you need to open the charger case. If it is dismountable, you will need an appropriate screwdriver. With the non-separable option, you will have to use sharp objects, separating the charge along the line where the halves meet. As a rule, a non-separable design indicates low quality chargers.

After disassembly, a visual inspection of the board is carried out in order to detect defects. Most often, faulty areas are marked with traces of burning resistors, and the board itself will be darker at these points. Mechanical damage is indicated by cracks in the case and even on the board itself, as well as bent contacts. It is enough to bend them back into place towards the board to resume the supply of mains voltage.

Often the cord at the output of the device is broken. Breaks most often occur near the base or directly at the plug. The defect is detected by measuring resistance.

If there is no visible damage, the transistor is desoldered and ringed. Instead of a faulty element, parts from burnt-out energy-saving lamps are suitable. Everything else was done - resistors, diodes and capacitors - are checked in the same way and, if necessary, replaced with serviceable ones.

In this article we will tell you how to charge a cell phone without an industrial network, in nature? Below is a version of a universal converter for charging any cell phones that have a standard adapter - a pulse charger (charger) for cell phones. Its use allows you to charge the batteries of any cell phones from a 12 V DC source, for example, from the on-board power supply of a car.

When traveling for a long time by car, or on a countryside family vacation in nature, the problem of charging a cell phone battery often arises. This, of course, can be solved by purchasing a specialized charger that operates from the vehicle’s on-board network. But in most cases, family members have different types of cell phones, so both the connectors for connecting the charger and the chargers themselves are different. Finding adapters for different types of connectors is difficult.

This problem can be solved in another way - by manufacturing the proposed 12 V DC to 300 V DC converter, which will allow you to charge cell phone batteries from standard chargers. True, the chargers themselves must have a transformerless input, i.e. assembled according to the circuit of a pulse voltage converter with a network rectifier (nowadays all “chargers” from cell phones are like this). The diagram of the proposed device is shown in the figure. This is a single-cycle, flyback voltage converter with external excitation. Timer DA1 assembles a controlled generator of rectangular pulses, which are supplied to the gate of a powerful switching field-effect transistor VT1. The voltage pulses on the secondary winding of the transformer are rectified by diode VD1, capacitor C5 is smoothing. The output voltage is stabilized by a unit consisting of zener diodes VD2, VD3 and transistor VT2.

After supplying the supply voltage, the rectangular pulse generator begins to operate. The generation frequency is determined by the parameters of the R1C2 circuit and is about 30 kHz. When transistor VT1 opens, current flows through the primary winding of step-up transformer T1 and energy accumulates in its magnetic field. After transistor VT1 is closed, energy from the secondary winding is transferred through diode VD1 to capacitor C5. When the output voltage exceeds the breakdown voltage of the zener diodes VD2 and VD3, current will flow through resistor R5 and the voltage across it will increase. This leads to the opening of transistor VT2, it connects the E input of timer DA1 to the common wire, which leads to generation failure and a decrease in the output voltage. After this, transistor VT2 closes, generation resumes, and all processes are repeated cyclically. Therefore, the output voltage is determined mainly by the total stabilization voltage of the zener diodes VD2, VDЗ.

The device uses resistors MLT, C2-23, oxide capacitors are imported, the rest are K10-17. The transformer is wound on a ferrite magnetic core Ш12х14 from the transformer of the line scan unit of the UPIMCT TV, the primary contains 12 turns of PEV-2 wire, PEL with a diameter of 1 mm, the secondary contains 310 turns of PEV-2 wire with a diameter of 0.31 mm. The field-effect transistor IRFZ44N can be replaced with field-effect transistors IRFZ24N, IRFZ48N, IRFZ34N, or with a bipolar KT825 with any letter index; in the latter case, the resistance of resistor R4 should be increased to 1 kOhm. Instead of two 1N5383B zener diodes, you can use three 1N5378B or 1N4764 zener diodes connected in series. It is also possible to replace a group of zener diodes with a rectifier diode KD212A. It is necessary to select an instance with a breakdown voltage of 300...320 V. To do this, the zener diodes VD2, VD3 are replaced with one diode KD212A. Temporarily, in place of capacitor C5, two capacitors K73-17 connected in series with a capacity of 0.47 μF for a voltage of 630 V are installed, and in series with the diode VD1 include another one, the same. By changing the KD212A diodes, the required output voltage is set. According to the author’s experiments, the breakdown voltage of these diodes is in the range of 280...380 V. After selecting the diode, the temporarily installed elements are removed and the standard ones are installed. At this point, the adjustment can be considered complete.

The converter parts are mounted on a prototype printed circuit board made of fiberglass using wire mounting. The board is housed in a plastic case measuring 85x50x45 mm, on the wall of which there is a socket for connecting the charger. The converter is connected to the vehicle's on-board network in the cigarette lighter using a special plug in which a fuse link FU1 is installed. When operating the converter, it should be borne in mind that in some chargers the network rectifier is made according to a half-wave circuit. Therefore, if, after connecting the charger, charging does not occur, it is necessary to turn its plug 180°, thereby changing the polarity of the voltage supplied to it. Two-year operation of the device has shown its high reliability and demand.

The above diagram is an excellent option for a mobile power supply! It can be modified, for example, increasing the output power. But is this necessary? The device actually does not require any settings, and if assembled correctly, it starts working immediately.

The article uses material from the Radio No. 1 magazine of 2010. Author - K. MOROZ, Nadym

During a long car trip or a country family vacation in nature, the problem of charging a cell phone battery often arises. This, of course, can be solved by purchasing a specialized charger that operates from the vehicle’s on-board network. But in most cases, family members have different types of cell phones, so both the connectors for connecting the charger and the chargers themselves are different. Finding adapters for different types of connectors is difficult.

This problem can be solved in another way - to produce the proposed 12 V DC to 300 V DC converter, which will allow you to charge cell phone batteries from standard chargers. True, the chargers themselves must have a transformerless input, i.e., assembled according to the circuit of a pulse voltage converter with a network rectifier. The diagram of the proposed device is shown in the figure.

This is a single-ended flyback voltage converter with external excitation. Timer DA1 assembles a controlled generator of rectangular pulses, which are supplied to the gate of a powerful switching field-effect transistor VT1. The voltage pulses on the secondary winding of the transformer are rectified by diode VD1, capacitor C5 is smoothing. The output voltage is stabilized by a unit consisting of zener diodes VD2, VD3 and transistor VT2.
After supplying the supply voltage, the rectangular pulse generator begins to operate. The generation frequency is determined by the parameters of the R1C2 circuit and is about 30 kHz. When transistor VT1 opens, current flows through the primary winding of step-up transformer T1 and energy accumulates in its magnetic field. After transistor VT1 is closed, energy from the secondary winding is transferred through diode VD1 to capacitor C5. When the output voltage exceeds the breakdown voltage of the zener diodes VD2 and VD3, current will flow through resistor R5 and the voltage across it will increase. This leads to the opening of transistor VT2, it connects input E of timer DA1 to the common wire, which leads to generation failure and a decrease in the output voltage.

After this, transistor VT2 closes, generation resumes and all processes are repeated cyclically. Therefore, the output voltage is determined mainly by the total stabilization voltage of the zener diodes VD2, VD3.
The device uses resistors MLT, S2-23, oxide capacitors are imported, the rest are K10-17. The transformer is wound on a ferrite magnetic core Ш12х14 from the transformer of the line scan unit of the UPIMCT TV, the primary contains 12 turns of PEV-2 wire, PEL with a diameter of 1 mm, the secondary - 310 turns of PEV-2 wire with a diameter of 0.31 mm. The IRFZ44N field-effect transistor can be replaced with field-effect transistors IRFZ24N, IRFZ48N, IRFZ34N or with a bipolar KT825 with any letter index; in the latter case, the resistance of resistor R4 should be increased to 1 kOhm. Instead of two 1N5383B zener diodes, you can use three 1N5378B or 1N4764 zener diodes connected in series.
It is also possible to replace a group of zener diodes with a rectifier diode KD212A. It is necessary to select an instance with a breakdown voltage of 300...320 V. To do this, the zener diodes VD2, VD3 are replaced with one diode KD212A. Temporarily, in place of capacitor C5, two K73-17 capacitors with a capacity of 0.47 μF for a voltage of 630 V connected in series are installed, and another one of the same type is connected in series with the diode VD1. By changing the KD212A diodes, the required output voltage is set. According to the author’s experiments, the breakdown voltage of these diodes is in the range of 280...380 V. After assembling the diode, the temporarily installed elements are removed and the standard ones are installed. At this point, the adjustment can be considered complete.
The converter parts are mounted on a prototype printed circuit board made of fiberglass using wire mounting. The board is housed in a plastic case measuring 85x50x45 mm, on the wall of which there is a socket for connecting the charger. The converter is connected to the car's cigarette lighter using a special plug in which a fuse-link FU1 is installed. When operating the converter, it should be borne in mind that in some chargers the mains rectifier is designed using a half-wave circuit. Therefore, if, after connecting the charger, charging does not occur, it is necessary to turn its plug 180°, thereby changing the polarity of the voltage supplied to it. Two-year operation of the device has shown its high reliability and demand. Chapter.