843rd: What is Qi 1.2?

Expansion of power transmission to 15W, but also needs to respond to the power receiving side.

　Several wireless power transmission and receiving standards have been added to Qi 1.1 and Qi 1.2 from the previous Qi 1.0.

　The difference between the 1.1 standards is that the sensitivity of the "foreign matter detection function" has been improved.This automatically stops charging when detecting abnormal situations that are affected by metal, other than the mobile terminal that you want to charge with the base station and the want to charge.

　When electromagnetic induction, the conductor in the magnetic flux used for power transmission generates electricity.For example, it cannot be denied that metal pieces other than mobile phones (smartphones) may be generated and fever.Measures for such events were taken.

　The largest thing that has changed in "Qi 1.2" is the "Expansion Electric Power Profile (BaseLine Power Profile)", which assumes the power of up to 5W, and to 15W.EXTENDED POWER PROFILE) will have been added.Previously, the terms were "low power" and "medium power (Medium Power)", but they were replaced with 1.2.2.

　The Qi1.2 extended power profile allows you to send and receive up to 15W.However, this power is a baseline if the baseline can be greatly reduced even if it supports the extended power profile, the base station and the terminal, even if it is wireless, and if either the base station or the terminal remains 1.1.Only 5W or less power flows.

　In addition, Qi is defined not only for "dense bonds" where the transmitter and the receiver are placed in a perfect overlap, but also in the standard "sparse bond".This means that if you have a circuit that resonates with the frequency (including receiving coil), the frequency generated by the oscillator coil is a specific frequency, so that power reception is possible in that mode.is.

　The smartphone compatible with Qi, for example, iPhone8 and Samsung Galaxy S8, can receive electricity even if the transmission side and the power receiving side are separated by this aphas.

　However, the resonance mode does not have a good power transmission efficiency.In the wireless power transmission, the degree of freedom of each transmission receiving circuit and the electricity efficiency are traded off.In other words, the circuit that can be placed appropriately has a poor power supply efficiency, and a mechanism that can strictly match the coil position has better power supply efficiency.

　Therefore, in Qi, the charger for mobile devices is basically charged in a "dust coil", that is, the power receiving coil for the smartphone for charging and the charging target, and the charging coils are charged in a close state.is.When charging, placing it correctly in the specified position is the basis of Qi wireless charging.

　In order to avoid such troubles, there is also a device on the power supply side, for example, a "moving coil" (a mechanism that automatically moves a power coil and an appropriate position).In this case, efficient charging can be done anywhere on the charging pad.