How wireless charging works on mobile devices

Wireless charging has become an essential option for smartphones and mobile devices.  What is a wireless charging device, and how does wireless charging work?

Wireless charging is charging the battery of a mobile device without using conventional wired connections. It works based on the principle of electromagnetic induction. One pair of coiled wires transfers energy in the form of magnetic flux. The international standard for wireless charging is known as Qi wireless charging.

Working principle – Electromagnetic Induction

Electromagnetic induction is a phenomenon of producing electric current under the influence of changing magnetic field. An electric current can be produced by a coiled wire when placed it in a changing magnetic field. Similarly, a wire or a conducting coil can produce a magnetic field when an electric current passes through it.

High-quality insulated copper Inductors are used in wireless charging units for better efficiency and power transfer.

The wireless charging system consists of two main units.

1. Transmitter unit

The transmitter unit is the base of the wireless charging device, which consists of a driver unit for power control and transmit coil (for electromagnetic induction). The driver unit will produce high-frequency pulses at below 300 KHz. These electrical pulses will be converted into magnetic energy and transfer it using transmit inductor (coil).

2. Receiver unit:

The receiver unit mainly consists of a receiver coil and some basic coupling circuits. It will receive the magnetic energy as flux changes and convert it into dc power which will be connected to the battery of the device. This unit will be a thin layer with a thickness of a few millimeters (it can even fit inside the device casing).

Applications of wireless charging

• Charging of mobile devices and laptop computers
• Charging of medical equipment
• Future electric cars and other vehicles
• Household devices
• Charging of sensor units for IoT and 5G applications

Limitations

Slow charging is one of the top disadvantages of wireless charging. Some of the base units are bulky in size and could produce some signal distortion to low-frequency systems. The efficiency of the wireless charging units is also often questioned.

Conclusion

A wireless charging unit has been improved to support high-efficiency requirements. Technology giants like Samsung and Nokia have already integrated wireless charging options into their new product lines. Apple analysts expect that the next generation of iPhones will have an integrated wireless charging option. Most of our future mobile devices will be equipped with top-notch wireless charging options.