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Qi standard for smartphones - simply explained

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What is wireless charging?
Qi standard: meaning and development
This is how the technology behind Qi works

The Qi standard is a crucial requirement for wireless charging - but what is behind the technology?

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Normally, the smartphone is connected to the charger in order to start the day again with a fully charged battery. But the Qi standard actually makes chargers superfluous. With the help of Qi, you can simply place your smartphone on the charging surface. How exactly wireless charging works and what the Qi standard actually defines is explained in more detail below.

What is wireless charging?

The trend is towards no longer charging gadgets or smartphones via a cable including a charger, but instead simply charging them where they are left to stand. For wireless charging, you need a charging station on which the mobile phone can simply be placed. You can now find this in the form of a pad or a marked charging area in the car, in the restaurant or at the airport. There are now such charging stations built into furniture for the home.

In this case, wireless charging refers to the technology with which the smartphones are charged without having to connect them to the power supply via a charging cable. So that different devices and charging stations from different manufacturers are compatible with each other, there is the Qi standard , which is explained below..

Qi standard: meaning and development

The Qi standard is far from being a new, rapidly developed technology. The standard was launched in 2008 - but was not implemented until much later in Germany. With the Samsung Galaxy II, released in 2012, Qi could be retrofitted for the first time. In addition to Samsung, the manufacturer Nokia also offered the feature with the Lumia 820 and 920. You may know the Qi standard from current flagship models. Almost all new high-end devices from the manufacturers support this feature. IKEA in particular made charging stations relevant within smart furniture. In the meantime, car manufacturers are also using inductive charging surfaces based on Qi in their automobiles. By the way, Qi is Chinese and is pronounced "chi" and means "life energy".

The Qi standard was established by the Wireless Power Consortium (WPC) to use the Qi protocol to ensure that the charging devices and receiving modules ensure interoperability. Simply put: any device with Qi can communicate with other Qi-supported devices using this standard. The WPC is an organization with over 120 member companies that promote inductive wireless energy transmission and develop processes and standards such as the Qi standard. The following manufacturers now support the standard established by the Wireless Power Consortium: Apple, Asus, Google, HTC, Huawei, LG, Motorola, Nokia, Samsung, Xiaomi and Sony.

This is how the technology behind Qi works

While the inner workings of wireless charging technology is quite complex, the basic concept is easy to explain. Electromagnetic induction is used for wireless charging. Two components are required for this - a coil in the charger and a coil in the consumer device such as a smartphone or other gadgets. If alternating current flows through the coil of the charger, a magnetic field is generated. As a result, alternating current now also flows in the other coil in the mobile device. The electronics convert this alternating current into direct current, which in turn charges the battery.

According to the Research Foundation Electricity and Mobile Communication, the energy efficiency of inductive charging via Qi was increased in 2017 attested to around 50 percent on behalf of the Swiss Federal Office. Power losses occur primarily when converting alternating current to direct current..