Sometimes I feel that the wireless charging mobile phone is very magical, and I really want to know how it realizes the wireless charging. Therefore, I have collected a lot of information and finally understood the principle. If you have the same curiosity, you can have a look.

1、 Electromagnetic induction

The charging base and the mobile phone terminal have built-in coils respectively. When the two are close, the transmitting coil generates a certain current in the receiving coil of the mobile phone based on the alternating current of a certain frequency through electromagnetic induction, so as to transfer the point energy from the transmitting end to the receiving end, and then power is supplied to the mobile phone from the charging base.

Because of its simple principle and easy production, and with the promotion of Texas Instruments, Philips, Toshiba, Microsoft, Panasonic, Samsung, Sony, and Qualcomm, this is the most popular way in the market. However, the wireless charging based on electromagnetic induction also has its disadvantages, among which the transmission distance is seriously limited.

2、 Magnetic resonance

The magnetron is composed of a large inductance coil with small capacitance in parallel or in series, and the same resonance frequency is a necessary condition for energy transfer. For example, if two coils act as resonators, the transmitter vibrates at 10MHz frequency and radiates electromagnetic field to the surrounding area, while the receiving end needs to vibrate at 10MHz frequency to receive the transmitted energy.

Compared with electromagnetic induction, wireless charging realizes long transmission distance and efficient power supply based on magnetic resonance, and it is a one to many power supply mode. However, because both sides need to be at the same resonant frequency at the same time, it is very important to tune the circuit, but it is not so easy.

3、 Radio waves

The principle is to convert environmental electromagnetic wave into current and transmit current through circuit.

This wireless charging mode has a transmission distance of more than 10 meters, which is suitable for long-distance low-power charging, and can also realize automatic charging anytime and anywhere. However, due to the low conversion efficiency, if this method is used, the charging time will be longer.

4、 WiFi wireless charging

This charging system mainly includes two parts, one is Wi Fi access point (router), the other part is customized charging sensor. It is worth noting that this method does not need to replace the traditional wireless router, only needs to deploy software and other solutions, and the charging function can coexist with the Internet access function, and will not affect each other.

The advantage is that it can be charged as you go, which is very convenient for users. The disadvantage is that it is not easy to locate the charging object and it is a waste of power.

5、 Ultrasonic wireless charging

The principle is to use ultrasound to deliver electricity 15 feet away. In this way, users only need to use a dedicated wireless charging sleeve, and they can walk around the house with their mobile phones while charging.

This technology is very safe, and the price of the receiver is also very cheap, small size, in addition to wireless charging, can also achieve data transmission. However, the final product may not meet the expectations in terms of price, power, speed and safety.

6、 Focusing light

This is a new wireless charging technology "autocharge" developed by Microsoft. According to the description, autocharge is a technology that automatically locates and charges a mobile phone on the desk. The system consists of two modules, one is a monitoring module with image processing function in the form of a camera, and the other is a charging module which uses UltraFire Cree xm-l T6 to focus LED light.

At that time, the charger will continue to rotate until an object that looks like a smartphone is detected, and then the smartphone will be remotely charged using a beam of solar power technology.