For better charging and faster data transfer, I would like to tell you about a technology that should help us get rid of wires as a class. As you might have already guessed, we will talk about wireless charging standards for smartphones and other gadgets. We will find out how they differ from each other, and, most importantly, how they work. Let's find out!
Just in case, let's start with the basics. Wireless charging, as the name suggests, is a method of transferring energy without using any contact surfaces. Those. This means not only the absence of wires, but also of any connectors or pins.
Today, wireless charging is not as popular as we would like. Manufacturers are not too willing to integrate such technology into their devices, and the mass appearance of charging stations in public places has not yet been observed. One of the problems, as in general in most electronics industries, is the lack of uniform standards. And that’s exactly what we’ll be talking about.
Qi
Currently, the most common wireless charging standard is Qi. It was developed by the Wireless Power Consortium (WPC). It is the Qi standard that is supported by many manufacturers of smartphones and tablets, including such monsters as Asus, Motorola, HTC, Huawei, LG, Nokia, Samsung, Blackberry, Sony and others.
The transfer of power occurs from the transmitter to the plate inside the device. For successful charging, the plate must lie (be in a parallel plane) with the transmitter, and the distance between them should not exceed 4 cm. The charging process itself occurs due to electromagnetic induction. The current passing through the primary coil in the transmitter creates oscillations in the electromagnetic field, which in turn creates a current in the secondary coil located in the plate of the recipient device.
The main difference from competitors, who also use the principle of electromagnetic induction, is the operating frequency. In the case of Qi, it is 100-205 kHz.
P.M.A.
Another standard that also uses the principle of electromagnetic induction is called PMA. Introduced by Powermat in 2012. It may not boast as much support from device manufacturers as Qi, but it still has some tricks up its sleeve. The thing is that the charger consists of two parts, and PMA decided to focus on the transmitter rather than the receiver.
It was recently announced that the popular coffee chain Starbucks will introduce PMA wireless charging to all of its locations in the United States by the end of 2015. You can find out more about this in one of the pages on our website. As you know, hipsters love to flock to Starbucks, so this way PMA can gain popularity.
So far, the standard is fighting exclusively in the United States. In particular, it is used by local telecom operators as a tool for healthy and not so healthy competition. This is how AT&T is promoting PMA, cutting out wireless charging of other standards in its operator devices.
Although PMA uses a physical charging principle similar to the Qi standard, electromagnetic induction, there are still differences. As already mentioned, they lie in the operating frequency, which for PMA is 277-357 kHz.
At the moment, PMA is quite behind Qi in popularity, and the mobile devices in which this standard is preinstalled can be counted on one hand. But still, the forces behind the promotion of PMA are quite strong, so it is too early to completely write it off.
The standard, created by A4WP (Alliance for Wireless Power), uses Rezence technology. It is even less popular than PMA, but is worth mentioning if only because it uses a different energy transfer technology.
The creators position the technology as “the next step,” because with its help you can charge devices at a much greater distance than in the case of electromagnetic induction, and objects such as books or other household items will not become an obstacle. Also, several devices can be charged from one station at once, creating a so-called smart charging zone around the dock.
The principle itself is based on the magnetic resonance effect. This is what allows you to significantly expand the charging area from one dock, as well as charge several devices at once. The transmitted power can reach 50 watts, which may be quite enough for a laptop. At the same time, the “mat” itself, unlike Qi or PMA, does not need to be built into tables if, for example, you want to implement such stations in your cafe. It is enough to secure them under the tables, this will not become an obstacle for Rezence.
Despite all the coolness of the technology, Rezence cannot yet boast of great success. The technology is supported by such monsters as Qualcomm, LG, Intel, HTC and others, but so far it has not reached commercial samples. However, A4WP recently signed a cooperation agreement with PMA, so it is quite possible that Rezence or its next incarnation could become the second generation of wireless chargers.
Conclusion
Personally, using wireless charging would allow me to almost completely eliminate cables when using a smartphone, because I now use them exclusively to recharge the battery. The function of data transfer was taken over by cloud services, Pushbullet, Airdrop and their analogues.
At the moment, mass implementation of any of the standards is still quite far away. Although Qi is now installed in most devices that support wireless charging, its meaning is often offset by the lack of a widespread network of “mats” and their high cost. Those. in fact, charging can only be used on a home/work mat, which, by definition, lies in one place. Or you will have to carry this “mat” with you, but you still have to plug it into an outlet with a wire, so all the charm of wireless charging disappears.
Potentially, the abandonment of wires, including those that not only transmit information, but also energy for batteries, is not so far away. The industry is evolving, standards are emerging and improving, so someday we must eventually arrive at a world without wires. In the end, Elon Musk himself will develop this direction, and he does not like to throw words to the wind.
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Technologies make the life of a modern mobile device user more convenient in a variety of aspects. If until recently the main competitive positions were concentrated in the devices themselves, today manufacturers are paying more and more attention to accessories and peripheral components.
One of them is How does this device work and how can it be useful to a modern user? The answers to these questions lie in the concept of communication itself, which excludes a wired connection. Wireless contact is designed to save people from the hassle of inconvenient connectors. In many ways, this idea was realized, but such devices were not without their drawbacks.
Features of wireless chargers
In the very first years of the spread of cellular phones, manufacturers had to make reservations when positioning such gadgets as mobile. The fact is that they were and remain mobile only conditionally, since they are dependent on the charger cable. Wireless charging has made it possible to remove all the conventions of such a designation for mobile phones and smartphones.
How does this device work? All technologies on which such charging are based are based on distance principles. It is important to note that the spread of wireless communication and information transfer technologies is not something new and surprising for a long time. Radio signal modules, Bluetooth and Wi-Fi sensors, network access points - all of this, to one degree or another, allows the transmission of information signals.
However, the novelty and fundamental difference with the wireless principle of operation lies precisely in the possibility of transmitting energy over a distance to power batteries.
Principle of operation
The most common design of such devices involves the presence of induction coils in the filling. In fact, they act as receivers as well as translators of electrical signals. When the charger itself is connected to the mains, a voltage is generated, after which a magnetic field is formed around the transmitting coil. Actually, after entering this field of the phone, wireless charging is activated.
How does recharging work? Due to the transformation of electromagnetic waves, which are transferred to the battery as electricity. In this case, the target object for power supply can be not only a phone or smartphone. Developers are guided by broad standards of batteries and batteries, which also apply to some models of tablets, cameras, players and other equipment.
Depending on the device model and its characteristics, different charging conditions are possible. For example, to understand how it works, you should familiarize yourself with the Qi energy transmission standard. Such a transmitter is capable of replenishing the battery capacity at a distance of 3-5 cm, that is, practically the mobile device must be in contact with the charger.
Wireless charging safety
The ability of chargers to transmit energy over distances rightly raises questions regarding their safety for users who, in any case, will be in the range of the induction coils. However, manufacturers claim that such devices do not cause any harm to health.
Examples include electric shavers and brushes that operate on the same principle of electromagnetic fields as wireless phone charging. How does the charging panel work in contact with other equipment and does it harm it? This question is also raised, but the manufacturers deny such a danger.
The fact is that the maximum power at which such devices operate is no more than 5 watts. This is not enough to have a negative impact even on devices sensitive to electromagnetic fields.
Devices from Samsung
One of the most successful developments in the Korean wireless charging segment is the Wireless Charging Pad. This is an optimized version of the basic family, which has eliminated the common problems of most similar first-generation devices. One of the main advantages of this model is the ability to interact with the phone’s battery regardless of its position relative to the functional platform.
In its commercial form, this version is represented by wireless charging that supports the WPC standard. This technology is different in that it is suitable not only for Galaxy smartphones, but also for most other Samsung phones. In addition, as the manufacturer notes, charging can replenish energy to half the capacity in just a few minutes.
Apple devices
It must be said right away that Apple products do not support wireless charging technologies. However, the manufacturer is looking for alternative ways to provide this feature to its users.
In particular, he recommends using accessories in the form of cases from Duracell. Therefore, the question of whether wireless charging works through a case will have a positive answer in the case of iPhones. If this method does not suit you, then you can use an iQi format receiver card. It connects via a special Lightning connector and is also hidden under a standard smartphone case.
Devices from Cota
Cota employees are also developing interesting proposals. They are not just mastering the concepts of specialized charging panels for mobile devices, but are striving to expand their range of action as much as possible. For example, in addition to phones and tablets, such a device can fill wearable electronics with energy. Moreover, for this it is not necessary to bring the device close to the active panel.
A small device the size of a bread box works at a distance of 10 m. The question arises: “How does wireless charging work with such a radius? Is it effective enough?” And here it’s worth returning specifically to wearable technology, including smart watches, bracelets and wristbands, since it is in working with these gadgets that the device demonstrates the most impressive performance. Obviously, phones and smartphones require more time.
Disadvantages of wireless charging
Like all technologies that radically change the way we use technology and electronics, wireless charging devices also have many disadvantages. Of course, the user receives a significant advantage, since he does not have to bother with wires and connectors, but the efficiency of filling the power supply with this method is noticeably reduced.
Most devices provide a charge over a longer period of time compared to the classical method. In addition, there are ergonomic inconveniences that modern wireless charging cannot yet get rid of. How does a wired charging system work? It requires connection to the device, after which it can be used for the same 30-60 minutes required to replenish energy. However, in the case of wireless technologies, not only does the charging time increase, but it also eliminates the possibility of using the device during this period.
Directions for further development
Actually, all directions of development of chargers operating without wires are aimed at eliminating the above-mentioned shortcomings and generally improving the basic characteristics.
The considerable weight of such devices also remains a big problem. In the mid-segment, the average device is a platform that can hardly be called mobile. However, it is worth noting here how wireless charging works for the Samsung S6 and devices for younger versions of the smartphone from the Charger Kit line. These are panel charging accessories that are attached to phones like protective devices and cases. This interface configuration minimizes the size of the charging infrastructure, but is not highly efficient.
Conclusion
It cannot be said that the emergence of wireless chargers has caused a stir in the market of accessories for mobile devices. Despite the novelty of the concept, the spread of this product is hampered not only by ergonomic shortcomings, but also by the cost at which wireless phone charging is sold.
You can make a similar device with your own hands at a lower cost. To do this, it is enough to organize a blocking generator with the function of an energy transmitter. As experienced craftsmen note, such a circuit will only require a homemade copper-based coil and one transistor with the accompanying wire infrastructure. Another thing is that in terms of reliability and safety, such a device will be noticeably inferior to the same branded models from Samsung.
There are several technologies for transmitting electricity through the air, including using lasers, sound waves, and other interesting methods. But so far only one can be called commercial - the use of electromagnetic induction, through which Faraday and Tesla tried to transmit energy. The most common inductive charging standard today has been developed by the Wireless Power Consortium for about seven years. This standard is called the Chinese word Qi - pronounced “chee” in English or “qi” in the Russian translation tradition. It is officially supported by almost all mobile phone manufacturers, from Samsung, Sony, Lumia phones, to small companies whose names mean nothing to anyone. Some American airports, British McDonald's and Starbucks are promised to be equipped with charging stations that meet this standard within a year, and this, as it becomes clear, is just the beginning of the list. This also includes new IKEA furniture and lamps with built-in charging panels - they will begin to be sold in Europe this month. Even Apple, which, as always, stands a little on the sidelines and does not officially support Qi, seems to still adhere to WPC principles in its watches.
How it works
Wireless charging using WPC technology involves the presence of induction coils in the phone and the charger: one acts as a receiver, the other as a transmitter of electricity. When the charger is connected to the mains, a voltage arises in it, and a magnetic field arises around its transmitter coil. When a phone enters this field, electromagnetic waves in its receiver coil are converted into electricity - the phone's battery begins to charge. The Qi standard implies that for complete energy transfer, the distance between devices should not exceed 3–5 centimeters. That is, they should practically touch each other. Therefore, most of the current induction chargers are small panels on which you need to place the phone. At the same time, their efficiency is about 75–80% - slightly less than that of wired chargers.
What are the pros and cons
If we talk about the average user, inductive charging has only one significant advantage. It eliminates the need to connect a cable to your phone (player, camera, watch and other small devices). And although it is called wireless, it does not actually remove the wire, since it is needed to connect the charging panel to the outlet. These panels also have other disadvantages: they are a little more expensive and on average charge one and a half to two times slower.
Is wireless charging dangerous?
This is probably the most popular question asked by the Wireless Power Consortium, and mobile manufacturers, of course, answer that it is safe. Manufacturers of electric shavers and electric toothbrushes are trying to convince everyone of this - the same induction principle has been used for a long time to recharge them. But it is worth keeping in mind that the electromagnetic waves through which wireless panels transmit energy belong to the spectrum of so-called non-ionizing (and therefore safe, unlike, say, X-ray) radiation. Electromagnetic waves of the same spectrum are used to transmit signals from radio stations, cell towers, and Wi-Fi routers. For example, a mobile phone signal is transmitted constantly and over much longer distances, but for its receiver to operate, only a small amount of power is required (within 1–2 watts). The maximum power of wireless panels of the Qi standard is significantly higher - 5 watts. But they (for now) work at extremely short distances, and they also turn off automatically (which means they stop emitting waves) if the device is charged.
In any case, no one has yet presented convincing evidence that Qi wireless charging (like a cellular signal) can threaten health. However, the Wireless Power Consortium is also working on more powerful wireless chargers (up to 120 watts) capable of charging laptops. But they are still being cautious with these devices, and no one seems to be releasing them.
Which devices support Qi wireless charging?
You can find out about this by searching on the WPC website. It is worth remembering that to carry out wireless charging you will need two things: a receiver and an energy transmitter. Some phones (and wearable devices) already have built-in charging modules, also known as receivers; all that remains to do with them is to select a wireless panel, also known as a transmitter. Other phones - all iPhones, for example - do not yet support this technology. In addition to the panel, you will also have to buy a special case or attachment with a charging module that connects to the smartphone via the usual charging connector.
Examples of wireless chargers
Samsung Wireless Charging Pad
PowerBot
Bestseller and, judging by reviews, the best wireless panel on Amazon. Compatible with Qi standard receivers. It comes with a micro-USB cable (which means it can be connected to a laptop or portable battery). Quite reliable and inexpensive model.
Perhaps the most exciting promise of recent years is a breadbox-sized transmitter that allows you to charge phones, smartwatches and bracelets, remote controls or gamepads at a distance of up to 10 meters. This is already a largely wireless technology, freeing you from fiddling with the charger. It doesn’t matter whether the phone is on the table or in your pocket: as soon as it is discharged and is within range of the transmitter, it will begin to charge it. However, the device being charged must be equipped with a special Cota receiver. The developers promise to begin delivering these receivers to device manufacturers at the end of the year.
iQi Wireless Charging Receiver
Finally, an example of how things are going with wireless charging of Apple phones. Since iPhones do not yet support the technology, crutches come to the rescue in the form of cases, attachments and other accessories. For example, Duracell cases for $120, which Apple itself recommends in its store. But the most amazing device for the same purpose is the iQi receiver card, which is connected via the Lightning connector and hidden under a regular phone case. The project, which successfully raised funds on the crowdfunding platform Indiegogo, can now be found on Amazon (although it’s probably better to try to wait for the seventh or eighth iPhone: one or the other, according to rumors, will have its own built-in receiver for wireless charging).
Nowadays, a person without a smartphone is a person cut off from life. It's hard to imagine that a few years ago a mobile phone was used only for communication. Now this little assistant gives us both access to the Internet and many applications, and wakes us up in the morning. The list of benefits provided by a smartphone can be continued endlessly. It is not surprising that a large number of gadgets have been invented for modern phones. One of them is a wireless charger, which we would like to talk about in more detail.
How can I tell if my phone supports wireless charging?
From the name it is clear that this is a gadget that allows you to charge your smartphone without using wires. It is a small stand connected to the network. There is an induction coil inside, which creates a small magnetic field around itself. If there is a smartphone within the radius of this field, it will receive electricity literally through the air. But there is one caveat - the smartphone must also have a built-in induction coil. It will serve as a kind of energy receiver from the charger.
The purpose of creating this device was to rid modern smartphones of charger connectors, and also to allow all devices in the house to be charged from one platform. The idea was a success, but why then don’t we see this technology in every home and don’t use it ourselves? The answer is simple - despite all the advantages, this miracle device also has disadvantages.
Pros and cons of a wireless charger
Wireless charging has a lot of advantages, but they all have their own cornerstone.
No wires
Without a doubt, this is a big plus. Wires have always been a weak point in chargers. With frequent kinks, the wire was easily damaged and tangled. Frequent recharging loosened the USB port on the phone, and sooner or later it needed repairs. But there is also another side to the coin. Refusal of wires reduced efficiency (efficiency) from 90% to 60–75%. Simply put, when using wireless charging, your smartphone will charge approximately 2-3 times longer.
Range of use
It would seem that there are no wires - there are no restrictions, and you can charge your phone simply while in the apartment. But no - the radius of use of the wireless charger is very modest (3–5 cm) and the phone will have to be placed on a stand. Another significant drawback will be the inability to use the smartphone while charging.
Price
The cost of a charger is quite variable, but it will always be more expensive than the usual charger.
Standards
I would like to talk about the standards that made the use of technology for transmitting electricity through the air possible.
Qi (“Qi”, after a term in Eastern philosophy) was developed by the WPC (Wireless Power Consortium). It is the most widespread and is supported by such giants of the mobile industry as Asus, Motorola, HTC, Huawei, LG, Nokia, Samsung, Blackberry, Sony and others. You can find out more about the standard and the list of supported devices on their official website.
The PMA standard also uses the principle of electromagnetic induction, but does not boast as large a list of manufacturers supporting their technology as Qi. It was developed by Powermat, which is currently trying to fight unhealthy competition from Qi.
This standard uses Rezence technology, which is fundamentally different from PMA and Qi. The strange thing is that the most unpopular standard has many advantages in comparison with its competitors. The advantages include:
- the ability to charge through interference (if you put a book between the smartphone and the charger, nothing will change);
- one platform can provide energy to several devices;
- work in close proximity to metal objects, etc.
You can view the full list of smartphones that can use wireless charging right out of the box on the official website https://www.wirelesspowerconsortium.com. I would like to note that most manufacturers have made sure that their product supports the use of this technology.
What if your smartphone is not on the list of supported devices, but you need to use wireless charging? If you have this question, then most likely you are a happy user of Apple products. The iPhone does not yet have the ability to receive electromagnetic signals. However, there is an alternative - purchasing an auxiliary accessory that will do this for your phone. It fits under a standard case and does not cause any discomfort.
Is wireless charging harmful to health?
Like any new technology, wireless chargers raise many questions. One of the most pressing is whether it harms health. Let’s immediately dispel this far-fetched myth. It will do you no more harm than an electronic razor using the same technology. The developers of the WPC standard themselves claim this.
We hope our article was useful and helped you understand the compatibility of your smartphone and wireless charger.
Finally, you can get rid of wires once and for all: the new generation of mobile devices supports QI wireless charging technology. CHIP will tell you how it works.
Nokia Lumia 920 smartphone on a QI wireless charging device Smartphones, e-readers, tablets - many of us have been owners of these devices for a long time. Their batteries require regular charging, and this is quite a troublesome task. In many cases, it is a problem, since most smartphones are discharged in one day. Therefore, it is long overdue to find a solution that takes into account both our forgetfulness and the constant need for electricity from mobile devices. The ideal would be a device, upon contact with which the gadget would immediately begin to receive a charge. To achieve this, the Wireless Power Consortium, which unites more than 100 IT companies, including Sony and Panasonic, has developed a unified standard for wireless chargers. It is called QI (pronounced "chee"), which means "energy flow" in Chinese. The first version of the standard appeared in 2010, but the implementation of the technology was sluggish. It was only in mid-2011 that the American provider Verizon began offering QI-enabled smartphones, including Galaxy models from Samsung. In 2013, the situation will change, which will be facilitated by the appearance of QI smartphones in Russia: the new top model Lumia 920 from Nokia has built-in QI support, and the back cover for wireless charging is optionally available for the Lumia 820.
Fast recharge for smartphones
According to the QI standard, the charging current power for a mobile device should be no more than 5 W. The standard does not provide for a specific method of energy transfer, but currently the inductive charging method is implemented, with both the transmitter and receiver equipped with coils. An alternating magnetic field arises in the transmitter coil, to which alternating current is supplied. As soon as the receiver coil comes under the influence of a magnetic field, an alternating current also arises in it. For the most efficient transfer of energy, it is necessary to ensure the best interaction of the receiver coil with the magnetic field. In this case, the optimal distance between the transmitter and receiver depends on the diameter of the coil. The size of the transmitter coil provided by the QI standard, depending on the design features of the transmitter, ranges from 30–80 mm. The required distance is approximately a tenth of this value, that is, both devices should be located close to each other. As the distance increases, the efficiency of energy transfer decreases catastrophically - from more than 70 to several percent. In addition, for optimal transmission it is also necessary to choose a good position of the coils in space. According to the QI standard, this task will be performed by a magnetic core in the center of the transmitter coil, which will be attracted to the magnet in the receiver.
Magnetic field as a means of communication
In addition to energy, a magnetic field also transmits information in the form of bits and bytes generated using phase modulation of the field. The connection between the transmitter and the receiver is established at the moment when a mobile device, such as a phone, is on the surface of the charger. The transmitter sends a pulse every 400 ms. If the voltage does not change, this means that no energy is being transferred. A drop in voltage indicates the presence of a QI-enabled receiver. After detecting the latter, the transmitter sends a more powerful pulse to “wake up” the receiver. He, in turn, “negotiates” with the transmitter about the charging conditions, that is, the required amount of electricity, current strength and frequency. After this, the energy transfer phase begins, the effectiveness of which the receiver reports to the transmitter every 32 ms, sending it data packets with information about errors that can be corrected if necessary. After the battery is charged, the receiver sends an “End Power Transfer” packet and the transmitter stops working.
The new version of the standard (1.1), which appeared in April 2012, provides for the use of more efficient chargers than the basic standard. Version 1.1 has a good chance of success, but not all companies are involved in the development and implementation of the technology: Apple does not support QI at all, and Samsung and Qualcomm are developing their own standard. Next year, Intel intends to begin producing ultrabooks with support for wireless chargers. To do this, the company will use a resonance method rather than induction, but it remains to be seen whether it will be QI compatible or not.
