Phones that support qi charging. Which smartphones support wireless charging: and what to do if not

If you are hearing about wireless charging technology for the first time, we strongly recommend that you read the material here.

On a string to the world

So, at MWC 2013 (Mobile World Congress, if anything), the presentation of wireless chargers looked somewhat generalized compared to the previous year. And, it seems, we have already seen this.

As a reminder, in 2012, Duracell dedicated a separate stand to wireless chargers, showing whole sets of devices for no more than $ 130 (US price). Among the new products, the company also introduced the Wireless Charging Card - a special insert that could be placed under the cover of almost every mobile device without harming the strength of the case. With a thickness of less than 1 mm, the liner does not lead to the formation of backlashes or loose fit of the lid to the body of the smartphone. The Wireless Charging Card today has many analogues, and this development was not the first of its kind.

In addition to Duracell, the wireless charging stand was also prepared by the Wireless Power Consortium, which, by the way, came up with the idea of \u200b\u200bstandardizing wireless charging technology (later called Qi, read as "qi"). The WPC includes dozens of the largest companies from around the world. Offhand, among others, Energizer, Samsung, LG, Philips, Nokia, Sony and, more recently, the same Duracell appear. In addition to Qi, the Association has earned another fat plus in karma, making all its certified products compatible. Those. The Qi-charger from Nokia can charge not only its own smartphones of this brand, but also any other gadget that meets the generally accepted standard. And if you suddenly carry a smartphone with a Duracell insert in your pocket, you can also charge your mobile at any of the Qi-supported bases.

There was only one stand this year. Technologically, the developments did not go far, but a couple of innovations nevertheless appeared: firstly, in 2012, it was possible to charge mobile devices using Qi, and nothing more. the maximum power of 5 watts was the maximum for this. The 35 watt charging prototype, also presented at the World Congress, did not look very confident, so the consultants immediately hinted that the device was still under development. At the current MWC, devices with a capacity of up to 120 watts have already been presented, which is enough to charge tablets.

The induction charging principle has not yet allowed manufacturers to change the shape of the distributing and receiving parts of the device. Wireless charging, in fact, is two coils - sending and receiving - between which a magnetic field arises. Often, we don't see the simple internal structure of the charger, but some manufacturers have managed to beat it. So, the special joy was caused by the ring-shaped PowerKiss adapters, thanks to which you can recharge even phones without a built-in Qi module.

PowerKiss, due to the release in several modifications of the USB connector, can be connected to absolutely any phone or smartphone, lay the gadget flat on the station and enjoy wireless charging. They are produced in different colors, which can also add to the treasury of useful characteristics of the device.

At MWC 2013, PowerKiss was shown again, and with them several very intelligent transmitter adaptation solutions. It is proposed to make it not in the form of a free-standing object, but, for example, discreetly adapt it to a specific interior: instead of the usual mat or stand, the base can be located in the handle of your sofa, be in the cover of the multimedia center or speakers.

The latter option has already found its embodiment in the products of TDK: Wireless Charging Speaker Q35 looks stylish, and, in addition to its direct purpose, it also charges your cell phones.

Issue price

Unfortunately, none of the listed devices fell into our hands, therefore we will limit ourselves only to general specifications and, in fact, price tags.

Devices that support wireless charging technology can be divided into two categories. Those in which this feature is still incorporated by the manufacturer are called "Qi Integrated". Phones out of the box that can handle Qi will be slightly larger than the rest. But you do not have to glue inserts under the cover or connect any other parts built into the case. You will need to buy a distributing base and that, in fact, is all.

The "Qi Ready" category includes devices that are Qi predisposed, but require a technological upgrade to ensure the full operation of the technology. In this case, both the transmitter and the receiver will appear in the shopping list.

True, you most likely will not find either the first or the second designation on the box of the device. Manufacturers often simply limit themselves to mentioning the possibility of connecting a smartphone or tablet to Qi. What kind of phone you got, you can only find out by opening the package. Or, say, from detailed reviews of this model.

See below for a table of Qi-enabled phones. Here are the compatible models released as of early 2013.

On sale, as you might have guessed, you can find both a Qi-charging kit and a base and a receiver separately. For example, the Philips DLP7210B kit is a case for the back of the device with a coil for receiving energy, as well as a base for transferring charge. The Qi charging kit for the Samsung Galaxy S4 is made on a similar basis.

Manufacturing subtleties

With Qi, the charger market has expanded significantly. Judge for yourself: if earlier we somehow did not find fault with the performance of adapters, now we have the right to twist our nose a little. The consumer chooses the device according to the shape, color and principle of attachment to the phone. At the same time, not limited to the offers of only one brand that has released a consumer-owned gadget.

Perhaps the easiest option is to place the receiver chip under the body of the device, if your smartphone or tablet did not initially receive one. This, firstly, will not affect the external condition of the phone: it will still be hidden under the cover! And secondly, it will not significantly affect the weight of the gadget.

The cost of the receiver plate is low: for example, a plate that is universal for all Samsung smartphones can be bought from $ 11 starting. A complete set (base and receiver) will cost about $ 62.

Another "inconspicuous" option for connecting a phone to Qi is a removable back cover with a built-in receiver. Such, as we have already said, are also in the catalogs of Nokia, Philips and Samsung.

The advantage of the back cover with a Qi-receiver is that, even though it somewhat thickens the body of the device, it also serves to protect the gadget. Such lotions do not have armor-piercing properties, but, in theory, the phone will be so whole.

A branded cover for Nokia Lumia phones will cost about $ 27. Note that the manufacturer produces them in several colors.

Another form of the receiver is the PowerKiss USB port. It costs about $ 34 / pc. (in the USA). This project is interesting in that it is focused, rather, not on individual, but on mass use: furniture with built-in Qi bases, as well as PowerKiss rings scattered over the surface, may soon appear at airports, waiting rooms at train stations, cafes, libraries, etc. other public places where such an innovation will deservedly receive popular recognition.

PowerKiss, by the way, solves the problem of connecting smartphones to Qi bases, which, in the presence of a non-removable back cover, did not receive the corresponding wireless charging module during production. Removable panels with a Qi module can still be attached to such smartphones. But when buying a kit, you need to carefully deduct the specifications of the device: not all receivers are capable of efficiently transmitting energy through the cover. And PowerKiss provides direct communication with the device's battery, therefore, the chances to charge the battery faster will be with just such a “ring”.

Speaking of efficiency. Most wireless chargers are less than 80% efficient. This does not mean that your phone will not receive something, it is just that the technology is still imperfect and you need to carefully follow the instructions in the operating instructions in order to increase the level of Qi performance in each case.

Rarely, but sometimes especially honest manufacturers admit that their device will not be able to work to the maximum, no matter how hard you try. For example, in the description of METRANS Wireless Transmitting Terminal MWT02 it is clearly stated: the maximum operating efficiency is 73%. At almost $ 78, this is a pretty clear warning.

If Qi, as can be seen in the example of PowerKiss, is only planning to be integrated into the interior, especially enterprising owners of wireless chargers manage to independently place the charging bases under the lids of bedside tables or coffee tables. The following video demonstrates how easily the latest technology lends itself to such creative experiments.

Now a little about the forms of the distributing bases.

The most common variant is a pad-shaped base, i.e. coasters.

Recall that in order to wirelessly charge a gadget, it must be close to the base. The maximum distance the device can be lifted today for continuous power transmission is only 4 cm!

Below you can see a test of Nokia's Qi system a la "charging with obstructions".

The horizontal position of the smartphone, on the one hand, is the most convenient for a typical scenario: he came in, threw the phone on the table. On the other hand, it is much more convenient to use a smartphone while recharging when the same platform has a certain angle of rise: not enough for the smartphone to slide off, but making it easier to work with the device if it suddenly becomes necessary.

Strictly horizontal bases can be found in the directories:

• Zens (charges $ 65 for one smartphone);
• Energizer (the Dual Inductive Charger base allows you to charge up to three devices: two - via Qi, and the third - via a standard USB port; the case of the model is slightly inclined, which is much better for an office charging option than a flat version; it costs $ 89);
• Duracell (the silver Powermat pad costs $ 34 and is designed to charge one smartphone, has a nice square shape with rounded edges);
• Nokia (DT-900 base is no larger than a computer mouse; not only suitable for Nokia phones; price $ 47).

Another "flat", but non-standard version is presented by TDK: Q35 Qi Wireless Charging Speaker costs $ 199 and represents the speakers placed in a modern cube case, on the top of which, in fact, the distribution coil is mounted.

Even after wireless internet connections became commonplace, wireless power transmission is still perceived by many as science fiction. Nevertheless, over the past few years, active research has been carried out in this direction, and now the first commercial devices that allow equipment to work without another type of wires are already available for sale.

The wireless charger sector experienced a real boom in the fall of 2009, when one company after another began announcing inductive charging devices. The first samples of wireless chargers were not certified, so they only supported a clearly limited set of rechargeable devices.

The situation changed dramatically in the late summer of 2010, when the Wireless Power Consortium, which included the largest electronics manufacturers, approved the new Qi 1.0 wireless power transmission standard with a level of no more than 5 watts.

The Wireless Power Consortium is currently working on the next version of Qi. It is known that the new version will allow you to transfer more energy at a distance and charge more "serious" equipment, such as netbooks, laptops, tablets.

This icon (logo) marks all electronic devices that support wireless charging of the "Qi" standard

Composition and principle of operation of inductive charging

Energy source. The basic principle of inductive charging is based on the use of the effect of electromagnetic induction. This requires two coils and an alternating current that will create a non-static electromagnetic field. The first coil is located in the transmitter and connected to the network.

Energy receiver. The receiver also contains a coil, the current in which occurs only when the electromagnetic field changes. This can be accomplished by moving the receiver in space or by using alternating current at the transmitter. If someone is afraid that a spark running between the transmitter and the receiver may strike him, then he is mistaken, since there is no charge transfer through the air - the alternating magnetic field created by the first coil simply forces electrons to move in the receiving device.

The basic principle of inductive charging is very simple and is based on electromagnetic induction. Unlike classic chargers, their wireless counterparts instead of a copper conductor use an additional conversion unit, similar to a conventional transformer, which leads to a slight decrease in efficiency.

The efficiency of this unit, according to different manufacturers, ranges from 50% to 90%. The Wireless Power Consortium cites an intermediate figure of 70%.

Benefits of the new wireless charger technology

Let's try to list all the advantages of the new technology:

Convenience.The owner of the phone simply puts the device on a small flat panel, without worrying about connecting wires and accurately positioning the device on the transmitter.

Versatility.Users of certified technology will be able to recharge it on any Qi-compatible charger.

Economy.Although the overall efficiency of inductive charging is lower than that of traditional charging, due to the almost complete absence of power consumption during idle (0.0001 W), they take the lead during long-term operation.

Practicality.The inductive charger is designed for the simultaneous "connection" of several devices. Unlike traditional chargers, this does not require additional power outlets.

Well, from the point of view of aesthetics, the absence of extra wires has always been a big plus.

Available wireless chargers

Remote transmission of energy is truly a new technology that has been developed for a number of innovative projects. In recent years, many large companies have investigated wireless power transmission for use in conventional technology. Suffice it to mention Intel, Sony, Sanyo, Fujitsu, Energizer. And although some innovative developments have not gone beyond the laboratory, some of the products are already available on the market.

One of the first to introduce inductive charging was Powermat. Its models support iPhone, iPod, BlackBerry, and more recently Android.

Qi Wireless Charger - Powermat3

Such a limited list is due to the fact that initially no telephone has a receiver to receive energy. It is installed in the smartphone later along with a new battery and, of course, special battery versions are available only for the most popular models. Usually the battery with the receiver is slightly larger than its predecessor, but in general, due to the thoughtful design, the device practically does not stand out.

GEAR4 takes a slightly different approach. Instead of a battery, a special case for the iPhone is included in the package with its charger, which must be on the phone at the time of recharging. The rubberized pad does not need to be removed after the battery is fully charged as it can perform normal protective functions.

The most common wireless charger today Energizer Qi one of the first to be certified in accordance with the Qi 1.0 standard and can charge up to three devices simultaneously. At the same time, an additional USB port is located on the transmitter body, which allows you to add another device

Wireless Charger - Energizer Qi

Wireless power transmission systems aren't just for smartphones. A year and a half ago, Energizer launched the Wiimote Induction Charging System for wireless controllers for the Nintendo Wii. Unlike analogs from other manufacturers, in this case it is not even necessary to remove the silicone covers from the Wiimote. The cost of the listed chargers included with the battery typically ranges from $ 50 to $ 150

Another Energizer device, but this time highly specialized. Designed exclusively for charging Nintendo Wiimote

Although the Qi 1.0 standard does not provide enough power to power large devices, some manufacturers have developed their own systems for recharging laptops. Over a year ago Dell introduced a 16-inch model Latitude Z with a body thickness of just over 1.25 cm and a weight of about 2 kg, which can be charged wirelessly while on a special stand. The starting price of the laptop was $ 3645, and now, depending on the configuration, it is around $ 2000.

However, the mass production of universal inductive chargers capable of charging laptops of any manufacturer will have to wait a couple of years.

The near future of wireless power transmission

It is obvious that in the near future all efforts of researchers will focus on solving the following tasks: increasing the efficiency of devices, increasing the amount of transmitted energy and distance. It is also expected that new models of inductive charging will be almost universal and will be able to charge mice, portable consoles, phones, cameras, GPS and other devices.

Probably, soon all portable gadgets and mobile phones will be equipped with Qi-compatible receivers by default, so that they do not have to be bought along with a new battery.

Fujitsu announced last fall that it will mass produce the next generation of inductive chargers in 2012, which can charge mobile devices 150 times faster than the first prototypes. In this case, the efficiency of energy transfer in such models will be at least 85%.

In general, given that a year ago Sony presented a working prototype of a system that transmits 60W of energy, and WiTriCity declared the presence of devices capable of transmitting energy over a distance of 2 meters, it is possible that such technologies will become familiar in a few years.

You can look into the future and a little further - now Nissan demonstrates a prototype of an electric vehicle charger capable of charging small electric vehicles in just 3 hours. At the same time, engineers argue that the effectiveness of such a system is the same or even higher than that of conventional wired charging of cars.

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Wireless charging technologies for electronic devices have been developed by manufacturers for a very long time. Perhaps the most familiar and popular real-world uses for these are some models of electric toothbrushes. In this case, the advantage of such a solution, in addition to the convenience of charging, is the absence of external electrical contacts, which are not very practical in a bathroom. It is also worth paying attention to the regular operation of this device and the absence of the need to charge the brush in other places.

However, the smartphone market has not yet seen a wide distribution of similar solutions, which seem to be very convenient. In our opinion, there are several reasons for this. The first two are quite typical for the majority of new technologies: an increase in cost and a small number of available "counterparts" - the wireless chargers themselves. But the more important reason is a significant change in the scenario for charging a mobile device. When using a cable, you only lose one thing - the ability to move your smartphone over a long distance. And in most cases this is not very important (besides, you can just use a long cable). At the same time, you can continue to use telephone conversations, the Internet, mail, multimedia and all other applications. You can't afford this with wireless charging. It without fail requires finding the smartphone on a special stand while charging. Although, of course, you can imagine an option with a speakerphone or a headset.

It turns out that in fact, wireless chargers can be of interest only in a limited number of scenarios - for example, in a docking station for charging at night or when navigating in a car. For frequent daily or emergency use today, they are not very convenient. However, the variant of the chargers in the cafe, which is already being tested, may also be useful. Over the past few years, smartphones have received bright high-resolution screens with a large diagonal and powerful multi-core processors, but the active life on a single battery charge has remained practically unchanged. If they were capable of guaranteed to last more than a day, the situation would be different - the user would only have to use the wireless charger at home, putting the smartphone on it overnight. It should also be noted that for popular devices such as tablets, wireless charging is less likely. In particular, they require a higher power supply than smartphones, and in addition, the stand will be too large. (By the way, it should be noted that during testing we came across the fact that in some combinations a certain fixed position of the smartphone on the stand is required for operation.) Using wireless charging with headsets or other accessories is also unlikely, the reason for the lack of such solutions will be the inability to use large enough reception rooms coils in these devices.

In general, the following advantages of a wireless solution can be noted:

• lack of mechanical / direct contact;
• the ability to use in an adverse environment;
• ease of use (in some cases).

However, there are also disadvantages:

• less efficiency;
• long charging;
• an increase in the cost, weight and size of a smartphone;
• the inability to fully use the smartphone while charging.

But it must be admitted that certain shifts have been outlined in this area recently. Not every manufacturer, even the largest one, has the strength to create a truly universal solution. It can be considered that the beginning of standardization was laid in 2008 with the creation. The variant they developed called Qi is today the only solution recognized by a large number of market players. In total, according to the consortium, at the time of this writing, almost 200 companies were represented in it, and there were more than 350 products on the market supporting this standard. Qi can be found in products from HTC, LG, Motorola, Nokia, Philips, Samsung and other manufacturers.

Another organization in this area is, formed in 2012. Qualcomm, which is part of it, is currently offering its implementation of the technology called WiPower.

It is also worth mentioning created in 2012, which also sets itself the task of developing and promoting the industry standard for wireless charging. Following him, in October this year, a working group was organized.

At the moment, you can find Duracell Powermat products on the market, but they are not widely used and are not used by smartphone manufacturers, so later in this material we will consider Qi solutions.

Technically speaking, a wireless charger uses an electromagnetic field to transfer energy from one device to another. If we talk about the current implementation of Qi, then here in the low power section the following characteristics are set: a distance of about 5 mm, a maximum power of 5 W. Recall that the power of five watts corresponds to the most common wired chargers with a USB interface and a current of 1 A. In addition to the coils themselves, special controllers are involved in the process that monitor the supply and reception of energy, and the control is a unit installed in the mobile device.

Below we will consider three solutions of this standard from different manufacturers in terms of usability, charging speed and compatibility.

Nokia

To enable wireless charging of its devices, Nokia offers two accessories: the Nokia Wireless Charging Plate (DT-900) and the Nokia Wireless Charging Pillow by Fatboy (DT-901). They differ only in design: the first is a strict plastic device, and the second is a soft and flexible "pillow". Both models are available in several vibrant colors to match Nokia's Lumia lineup. The rest of the characteristics are the same: support for the Qi standard, an external 12 V 0.74 A power supply with a 1.8 m cable.

We used the DT-900 for testing. The body of the stand is made of plastic, in our case it is a bright red color. Its dimensions are relatively small - about 120 × 60 × 11 mm.

The upper matte surface has the manufacturer's logo in the center, around which there is a low rubber rim. It allows you to keep your smartphone on the charger. Note that the large size of the panel is roughly equivalent to a smartphone with a 4.5 ″ screen. So modern large devices will cover it completely.

The edge and bottom surface are glossy. On one of the short rounded ends there is a power supply input, and on the opposite side there is a white indicator of charging. On the bottom of the panel there is a rubber insert that prevents slipping.

The supplied cable is red, but the power supply itself is white. It is worth paying attention to the parameters of this unit - it produces 12 V 0.75 A, which is significantly more than standard wired chargers give out. In particular, the standard AC-16 is designed for 5 V 1 A. It can be seen that the power losses are significant.

The list of compatible devices includes models from Lumia 720 and above. However, only Lumia 920 has a built-in receiver, for the rest you will need to purchase an additional back cover, which communicates with the device through the contacts located on the back of the smartphone. In particular, when working with the Lumia 1020, the lid increases the weight by 30 g and the thickness by about 2 mm. Perhaps this solution is more interesting than the built-in module in the Lumia 920. At least until such technologies are used everywhere.

The device turned out to be quite convenient in operation. Small size freely allows you to place it on a table, bedside table or shelf. The built-in indicator glows during charging, which starts literally a couple of seconds after placing the smartphone on the stand. Note that if you use large smartphones, this indicator may not be very visible. Also pay attention to the non-standard power supply and connector. The other models discussed in this article can be "transformed" into regular chargers and used with most smartphones by simply disconnecting the Micro-USB cable from the stand.

We carried out the first charging test together with Nokia Lumia 920. The test showed that the wireless charger can work even with a completely discharged device, which undoubtedly should be considered a plus of the solution. As for the full charge recovery time, with the DT-900 it turned out to be almost the same as with the standard wired power supply - about two and a half hours. So the charging speed in this case can be considered high, but the main thing is that it will be convenient for the user to predict the required time, since it does not depend on the option used.

Compatibility test with Samsung Galaxy S4 equipped with a proprietary wireless charging cover was successful. The smartphone was able to fully restore its charge in about 3 hours 10 minutes. At the same time, it is also possible to start working with a completely discharged battery.

Note that in the arsenal of Nokia there is an unusual model of an external battery with wireless charging - Nokia Portable Wireless Charging Plate (DC-50). The cost of Nokia DT-900 at the time of this writing was about 2600 rubles. Branded covers with receiving modules were offered for 1000-2000 rubles, depending on the model.

Samsung

Samsung has taken a slightly different approach to the configuration. Its S Charger Kit includes a charging stand and a new smartphone cover with integrated charging circuits.

When used with the Samsung Galaxy S4, it increases the weight of the device by 20 g, and the thickness by about 2 mm. It is interesting that the currents are indicated on the components: the input requires 5 V 2 A (this is how much the standard unit gives from this smartphone), and at the output you can get only 5 V 0.65 A.

The stand body is made of plastic. Its dimensions are about 161 × 91 × 12 mm. A gray semi-gloss material is used for the top panel. Its concave shape helps to hold the smartphone in position. The manufacturer's logo is visible in the center. However, if we talk specifically about the Galaxy S4, then it is noticeably smaller than the stand - the dotted line just corresponds to the size of the smartphone.

The main body is glossy white. In the center of one of the short ends there is a Micro-USB socket. To the side of it, on the upper edge, there is a green LED, which lights up when the smartphone is installed on the stand and charging starts. The place for the indicator was not chosen very well - it would be more convenient to see it on the opposite side. However, due to the large size of the stand, this is not very important. Most of the bottom is made of rubber, which allows the stand to hold firmly to the table.

The time to fully charge the Samsung Galaxy S4 is about three and a half hours. Testing the operation using a 1 A power supply showed that in fact the requirement for a two-amp model is not justified, a less powerful unit will be sufficient. This change does not affect the wireless charging time. Note that this configuration is also capable of recovering a fully discharged smartphone.

Recall that when using the bundled wired charger, the charge recovery time is about two and a half hours. At the same time, up to 90% the charging speed is quite high, but in the last ten percent it decreases.

In domestic stores, this kit is offered for about 3,000 rubles.

PowerQi

The presence of the standard allows different companies to produce compatible devices, not just smartphone manufacturers. In particular, we managed to find an almost "unnamed" version of the PowerQI T-100 wireless charger for testing.

The package includes a stand, a power supply unit (5 V 1.5 A) with a Micro-USB cable and a special receiver unit. The last element is usually individual for each smartphone model, in our case it was the antenna and the control unit for the Samsung Galaxy S4. In terms of cost on foreign trading floors, approximate guidelines are $ 35 for a charger with a power supply unit and $ 10 for a receiver unit.

The stand is made of white glossy plastic and measures 150 × 80 × 10 mm. The flat top has slightly beveled edges and lacks any rubberized elements, so the smartphone does not hold well in place. The gray paint panel bears the company and model name and the wireless charging standard logo. The stand is supported by four rubber feet.

The LED glows green when external power is available, and when the smartphone is installed for charging, it changes color to blue. We also note the sound signal at this moment, which allows you to be sure of recognizing the device and starting charging.

The receiver unit is a flat antenna and a small board with a Texas Instruments controller. It is supposed to be installed under the standard cover of the smartphone with connection to the contact pads present on the case.

Note that the receiver has an output current of 600 mA. For smartphones that do not have such an opportunity, there are options in the form of covers with a connection via standard Micro-USB. Interestingly, this antenna seems a little smaller in size than in the standard Samsung accessory; this may lead to the need for more accurate positioning of the smartphone on the transmitter. In our testing, this situation arose with the Nokia charger due to its compact size.

The charging time of a smartphone with a proprietary cover on the PowerQi stand is approximately 3 hours 30 minutes, so from the point of view of transmitters, these models turned out to be the same. Other combinations of the receiver and transmitter give similar results, including the possibility of restoring the charge of the smartphone with a completely discharged battery.

Conclusion

Many companies are showing interest in wireless charging technologies for smartphones. However, one should not expect any revolutions here. There are a lot of players on the market, it is difficult for them to come to an agreement with each other, in addition, the familiar problem of “chicken and eggs” is imposed. So today it is probably not worth considering the presence of a built-in or optional wireless charging module as mandatory for top-end devices.

In this article, we looked at several options for solutions developed according to the Qi standard. They showed good compatibility and were generally quite functional. Some concern is caused only by the relatively low possible power in this Qi modification, which does not allow for a quick charge recovery of modern devices with high-capacity batteries. However, if we consider these solutions as a night charger, they will be quite enough for most smartphones. As for active work scenarios, for example, navigation in a car, a situation is quite possible here when the wireless docking station will not be able to restore the battery charge while running resource-intensive applications, but will only act as an additional power source, reducing the discharge rate of the standard battery ...

In any case, Qi technology can be considered already mature enough and suitable for use not only by enthusiasts, but also by ordinary users who find this scenario useful for themselves. Moreover, it is not at all necessary to use original accessories - solutions of lesser-known companies offered on Internet sites at a relatively low cost may also be suitable.

Qi is the global international standard for wireless charging of a variety of devices. The standard is being developed by the Wireless Power Consortium (WPC). The name Qi (read Qi) is based on the pronunciation of one of the most important Chinese characters. Qi is the fundamental foundation of Chinese philosophy and is most accurately translated as vital energy. It is generally known that electrical energy can be transmitted without the use of conductive elements. Qi is based on one of the methods of wireless transmission of electricity over a distance - the method of induction transmission. This method was known to mankind back in the 19th century. Most often, its implementation can be found in the production of most electrical transformers.

The essence of this method is as follows: an alternating electric current passing through the primary winding of the transformer, due to the phenomenon of electrodynamic induction, creates an alternating magnetic field acting on the secondary winding. This field induces an electric current in the secondary winding. Moreover, the closer the primary and secondary windings are, the higher the efficiency of electric current transmission. As one winding moves away from the other, more and more of the magnetic field is wasted without transferring energy. This property determines the main disadvantage of this method - the short distance of its action.

The Qi standard is primarily aimed at home use of wireless chargers, where there is no need for a long distance between the receiver and transmitter of electricity. But there is a consumer need to get rid of inconvenient charging cables, contact stands and other devices. In this case, the recommended distance between the charging platform and the device being charged should not exceed 4 cm.

Such circuits have long been widely used in the designs of electric toothbrushes, induction cookers, and are now very actively implemented in the mobile phone market. Today, all leading manufacturers of cellular technology have included the ability to charge their phones using the Qi standard. To activate the process of recharging the phone's battery, you just need to put it on a special compact charging panel, the panel, in turn, must be connected to a power source (to a regular household outlet).

Qi achieves high efficiency in wireless power transmission through the use of resonance effects. The transmitter and receiver are tuned to the same frequency. This is done by incorporating capacitors into a flat coil or single layer solenoid, which is a transmitting coil located in the charging pad. In this case, the transmission efficiency is 80%. For comparison, the efficiency when charging a phone in a traditional wired way is from 75% to 95%, and it is simply impossible to achieve an efficiency of 100%!

In cell phones that support Qi technology, the receiver coil is made in the form of a very thin copper spiral, which is attached to the back of the phone from the inside. The thickness of such a receiver is negligible and installation does not cause great difficulties, therefore it can be placed under a standard cover without additional investment. As an alternative to this option, it is possible to replace the standard phone cover with a new one with an already built-in receiver.

WPC certified chargers and gadgets according to the Qi standard do not use ionizing frequencies, so they cannot have harmful physiological effects on humans or animals. Also, most modern chargers and smartphones have built-in protection mechanisms based on thermal control. They are also able to detect the presence of foreign objects in their field of action, which also provides additional safety of use.

If the mobile phone and charger support the QI standard, they recognize each other as soon as they touch. After the exchange of the necessary information, the process of energy transfer begins: the transmitter coil generates a magnetic field, through which energy is inductively transferred to the receiver.

1. The transmitter "charger" first detects the presence of a QI-enabled device that needs to be energized. It then generates alternating current in the transformer. A magnetic field arises in the coil, through which energy is inductively transferred to the device to be charged.

2. Communication The controllers of both devices "agree" on the terms of the transfer of energy (Power Transfer Contract), thus ensuring uninterrupted and efficient charging of the device. Data exchange is carried out by means of phase modulation of the magnetic field.

3. Receiver To store the alternating current generated by induction in the battery, the receiver needs to convert it to direct current and change the voltage accordingly. Finally, the receiver controller signals that the battery is fully charged and the charger stops the process.

Another important feature of the Qi standard, which is undoubtedly worth mentioning, is the presence of a data exchange interface between the charger and the smartphone. The exchange takes place at a speed of 2 kbit / s and allows you to transmit and receive information about the residual charge level of the battery, test it and, upon completion of charging, disconnect the transmitting device, without consuming unnecessary electricity and without harming the battery by overcharging it.

Today, the development of Qi can only be compared with Wi-Fi - the general global standard for wireless data transmission. Now, almost anywhere you are, you can access the Internet through a Wi-Fi hotspot. All mobile devices - smartphones, tablets, laptops are equipped with Wi-Fi modules. And it is no secret to anyone that it is wireless technologies that are our, already practically arrived, future.

The next step to make our lives easier is the massive use of wireless universal chargers. To meet this challenge, the Wireless Power Consortium has developed an international Qi standard.

The Wireless Power Consortium currently unites more than 140 hardware and device development organizations. The idea behind Qi is simple: any device with the Qi logo can be charged from any charger with the same logo. No more need for unique wired chargers for specific devices, no problems with cables and no problems with adapters when traveling. Qi is an international standard, which means your device can be charged without wired charging, over the air, wherever you are. You just have to find the nearest place equipped with charging surfaces. There are more and more such charging stations all over the world. Soon wherever there is Wi-Fi, there will be Qi! You will be able to charge in offices, hotels, airports, cafes and restaurants. In the near future, one of the main criteria for choosing a new gadget by a buyer will be the presence of the Qi logo on it. Already, such market monsters as Samsung, Apple, Sony, Ericsson, LG, HTC and Motorola use Qi technology in their devices. In this case, the device can already contain a receiver for wireless charging (Qi-solution), or it can be supplemented with it (Qi-ready).

The number of smartphones with Qi already on the market is more than 100 different models, and their number of sales has already exceeded 8,500,000 units. The most popular among these are Samsung's flagship Galaxy models, Apple's iPhones, and Nokia's flagship Lumia range.

Even Toyota has installed a built-in Qi charging pad in its latest Avalon Limited car. Next to the driver, on the center console, there is a special panel, placing the phone on it to start charging it. Thanks to the efforts of the Wireless Power Consortium, the wireless charger ecosystem is also growing rapidly. Many network leaders such as Virgin Atlantic and The Coffee Bean & Tea Leaf have contracted to equip their café tables with Qi charging surfaces. In the near future, the number of places where you can charge your personal device wirelessly will increase dramatically. And you can charge your smartphone at home or in the car wirelessly right now, you just need to purchase a Qi-certified charging pad from us.

Prospects for the development of a wireless charging system for Qi devices depend on the speed of the spread of this standard in the world and on the support of its market leaders. In fact, its distribution is already becoming widespread. All the leaders of the global industry and industry have already included it in their devices. It is also worth noting the lack of competition in this market. The presence of one common standard for all suits everyone. Moreover, in fact, all other interfaces have already been made wireless. And if nothing needs to be connected to the device, then it can be made completely or partially sealed. With such a smartphone it will be possible to communicate at least under water. And what is perceived with humor today will become a common everyday reality tomorrow.

Qi is the Chinese word for “flow of energy” (pronounced chi in English) and is the universal standard for batteries such as iPods, cell phones, and cameras.

Power transmission occurs due to the fact that the receiver receives energy not through a traditional cable, but in a contactless way, thanks to the use of electromagnetic fields. The principle is very simple: the Qi transmitter, which is the base station, directs the necessary energy to the receiver.

Description of technology

The Qi wireless charging standard is based on magnetic induction between the flat coils of the transmitter and receiver. The primary and secondary windings form two pieces of a heartless charger circuitry shielded on the lower surface of the primary and upper secondary coil. This, as well as the proximity, ensures acceptable power transmission efficiency. Moreover, it minimizes the exposure of users to the magnetic field.

Typically, the base station has a flat surface on which one or more mobile devices can be placed. This ensures that the vertical distance between the primary and secondary windings is small enough. In addition, there are two ways to align the windings horizontally.

In the first case, the user independently sets the secondary winding opposite the primary one on the interface surface using the prompts of the mobile device.

The second method, called free positioning, does not require active human participation. In one implementation, several primary windings are created for this. Another option uses mechanical means to move the primary coil under the secondary.

Structural elements

The power transmitter consists of two main functional units, namely a power conversion unit and a communication and control unit. The element of the first, generating a magnetic field, is the primary coil. The second changes the transmitted power to the level requested by the receiver. In addition, the base station can contain more than one transmitter to serve multiple mobile devices, since one primary coil communicates with only one secondary coil at the same time. Finally, the system unit provides power and controls the operation of multiple transmitters.

The gadget contains an energy receiving unit, which is a secondary winding, and a communication and control unit. The latter adjusts the transmitted power to a level acceptable to the subsystem connected to the receiver's power output. An example of such a subsystem is a battery.

Communication stages

After activating the communication and control unit of the transmitter, it sends a signal to the receiver to receive a response confirming the presence of a Q-compatible device.

Upon receipt of the request, the receiver enters the selection phase. If the suggested voltage is high enough, then the ping phase begins.

Upon receiving a response from the transmitter, the mobile device sends a signal strength packet and enters the identification and configuration phase, or sends a power transfer complete packet and remains in the ping phase.

An identification packet and management packets are then sent. The receiver enters the charging phase. At the same time, it controls the transmission of energy by transmitting control packets to the base station, which contain information on adjusting the primary winding current, on the received energy, on the charging status, on the completion of the transmission.

What is a Wireless Charging Point?

Qi charging is universal because it provides compatibility between mobile phones and different manufacturers. The only condition is that both parts - transmitter and receiver - must comply with the Qi standard.

Thus, any Qi wireless charger will fit any Qi mobile receiver, regardless of make and model. Many cell phones from different manufacturers, including Samsung, Nokia, LG, Sony, HTC and Motorola, are already Qi-compliant and therefore can be connected to any charging station that meets its requirements. The number of compatible gadgets continues to grow as more and more companies support wireless power transmission technology. This allows battery-powered electronics to be charged with a single power source.

How it works?

The mobile charger is not the newest invention. Inductive power has been used in electric toothbrushes for many years. The process uses the resonant inductive coupling of the base station transmitter and the mobile phone receiver. The primary coil constantly sends a test signal to the sender to check for a change in capacitance or resonance, indicating the presence of a compatible phone. The transmitter modulates the charge and checks if the Qi wireless charging standard is supported.

Once compatibility and energy requirements have been taken into account, the process of inductive energy transfer begins. In this case, contact between the receiver and the transmitter is maintained. Once the battery is fully charged, they will go into standby mode. Universal charging is activated and transfers energy only if the connected gadget is on it.

The power transmitting and receiving coils are specially shielded to reduce electromagnetic radiation.

The main features of the technology

• A method of contactless transmission of power from a base station to a mobile device, which relies on near-field magnetic flux density between the coils.
• Transfer about 5 watts of power using a suitable secondary coil (having a typical external dimension of about 40 mm).
• Work at frequencies from 100 to 205 kHz.
• Support for two methods of placement on the base station surface:
  • guided positioning, where a user is assisted in correctly positioning a mobile device in a location that supplies power through one or more fixed points;
  • arbitrary placement on the surface of the charging station.
• Simple one that allows your phone or tablet to guide the process.
• Considerable design flexibility for integrating the system into a mobile device.
• Low standby power consumption (depending on implementation).

One for all

How convenient would it be to have one Qi charger for all phones, music players, cameras without a lot of tangled cables?

As countless new smartphones sweep the world, battery life is getting shorter. And every manufacturer and even every gadget has its own charger. And with each purchase, their number increases. Ultimately, the user is lost in a pile of various power adapters. Thanks to Q-technology, they become unnecessary, and the tangled tangles of cables disappear, and these are far from all the advantages of this technology.

Just as Wi-Fi has become the global standard for wireless Internet connections, and Bluetooth has eliminated the need to hold a phone in your hand, so Qi is becoming the global standard for inductive charging of gadgets with batteries.

Is electromagnetic radiation harmful?

Experts are divided. On the one hand, many scientists confirm that a small amount of electromagnetic radiation from wireless charging is not harmful. Others talk about the great danger to which the human body is exposed.

So how much electromagnetic energy is emitted by the Qi system? Very little. The Qi principle has been applied in electric toothbrushes for many years without affecting human health. The diagram of the charger is such that, due to the small area of \u200b\u200bits action, electromagnetic radiation is extremely limited. It exists only in the immediate vicinity of the wireless transmitting station and only when the gadget is on it. Electromagnetic radiation is further reduced by additional shielding in the transmit and receive coils.

Wireless Power Consortium

The Wireless Power Consortium (WPC) was founded on December 17, 2008. At the same time, a unified program for the development of this technology was approved.

The Qi wireless charging standard ensures its versatility for all Qi-compatible electronic gadgets. This means that every device compatible with it can be charged at any Qi-compatible station. WPS has 250 members including market leaders Samsung, Nokia, LG, Panasonic, HTC, Sony, Microsoft and Motorola, making it the largest alliance of manufacturers supporting wireless charger types.

With the increasing number of products using Qi, it is important to ensure that each mobile charger works correctly with all supported Qi gadgets, says WPC Chairman Menno Treffers. This is facilitated by a constantly updated database created by Testronic, which makes it easy to determine if a new product will be compatible with previously certified products. Qi wireless charging standard has become one of the most important technical developments for phone and tablet users, which are now used daily in work and life.