How wireless charging works on mobile devices

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

Wireless charging basically charging of mobile devices 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. 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. Similar way, magnetic field can be produced by a wire or a conducting coil when an electric current pass through it.

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

Wireless charging system consists of two main units.

1. Transmitter unit

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

2. Receiver unit:

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

Applications of wireless charging

• Charging of mobile devices and laptop computers
• Charging of medical equipments
• 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. Efficiency of the wireless charging units is also often questioned.

Conclusion

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