Wireless charging is something that proponents can't put it down to, but another part of the people question it's slow charging, short charging distance, and essentially pants and fart. Whether you love it or not, you can't deny that wireless charging really needs to be popularized. It's coming.
For wireless charging, our expectation is of course unlimited, charging anywhere in the free space.
Of course, the ideal is very full, and the reality is very skinny. There is not much advantage in wireless charging compared with wired charging with the current technology. In addition to the convenience of using the charging and charging, the charging speed cannot be compared with the fast charging of the cable. It is not comparable to the needs of some users for using mobile phones while charging.
However, for some users, wireless charging is now available. In some scenarios where mobile phones are not frequently used, wireless charging can be used to its advantage.
Wireless charging technology
The core principle of wireless charging is based on electromagnetic induction. The principle is not complicated. Currently, there are two main technical branches in the industry. One is the magnetic field induction technology represented by the Qi standard, and the other is the magnetic resonance technology represented by the AirFuel standard.
In principle, magnetic resonance is A better solution, it supports farther charging distances, and can support multiple devices charging at the same time.
However, magnetic resonance technology is not yet mature, and through the stacking of multiple coils, the Qi standard wireless charger can also be used to charge multiple devices at the same time.
However, magnetic resonance is still the future direction of wireless charging. Qi also incorporated magnetic resonance technology into its standards. It can be seen that near-distance power transmission is not unachievable.
Wireless charging devices on the market
Currently, the wireless charging standards adopted by smart phones and consumer-grade wireless chargers in the market are mostly Qi. Therefore, as long as the mobile phones support Qi wireless charging, theoretically all wireless chargers using the Qi standard are compatible (including special hard-to-serve iPhone)
However, different mobile phones and wireless chargers are actually different in charging efficiency. For wireless chargers, only the input and output powers are generally listed. However, for the mobile phone, the received power is the key indicator of the charging efficiency. Said that the receiving power is about 75% of the output power.
Charging board side
At present, the mainstream wireless charger mainly uses Qi's Basic Power Profile configuration, supports 10W output, and has a conversion rate of about 5W~7.5W.
However, wireless chargers using the Extended Power Profile configuration standard have been born one after another this year and can support up to 15W of output power, which is equivalent to about 10W of received power, which can greatly increase the wireless charging speed of mobile phones.
Mobile terminal
Since the wireless charging board has power limitations, the phone is naturally the same. Currently, mainstream smart phones (mostly using Basic Power Profile configuration) support wireless chargers with 5 to 10W output power.
For example, Samsung Galaxy S series phones can support 10W wireless charging, while Apple iPhone 8/8 Plus and iPhone X can support 7.5W wireless charging, of course, converted into receive power will be lower.
In addition, smartphones supporting the relatively fast wireless standard Extended Power Profile are also being launched this year. Currently, there are familiar Sony XZ2 series and LG V30 series. The received power can reach about 10W, but it needs to be supported with the same support for Extended Power Profile. Wireless charger.
In summary, different mobile phones need to match different specifications of wireless chargers, but for most mobile phones, wireless chargers supporting 10W output are sufficient. In addition, many wireless chargers do not necessarily come with charging heads and data lines. , need to choose according to their input power and fast charging standards.
Although iPhone 8/8 Plus and iPhone X are compatible with the Qi standard, not all Qi wireless chargers can make it 7.5W fast charge.
In addition to power also need to pay attention to?
FOD foreign body detection
Foreign object detection of the FOD should be the basic safety function of the wireless charger. When a metal foreign object is sandwiched between the mobile phone and the wireless charger, the wireless charger will sense and cut off the power to prevent the metal foreign body from overheating.
However, the FOD function can't be judged by looking at the promotional parameters. Only through the actual measurement, we can see the specific performance. Most of the wireless chargers in the market are qualified for FOD detection.
cooling problem
The output power of wireless chargers is not constant, but the peak power is mainly determined by the design materials and cooling methods of wireless chargers. We recommend to purchase models with active cooling fans. Although thicker, the peak power is generally output. The time is longer.
Charging distance
Qi wireless charger's maximum charging distance is about 10mm, so each protective case can also be charged, do not need to 'un-light' the phone to charge.
With the development of the Qi standard, the cost of wireless charging technology has slowly been reduced. More and more products cost around 100 yuan. The experience cost is considered low. Currently, Xiaomi Huawei is trying to add wireless charging to its products. The wireless charging function will have greater popularity in the next two years.
It is not our style to say that light is not practiced. Next, we will conduct cross-testing on some wireless chargers and smart phones that support wireless charging in the market. Stay tuned!
