The latest version of Qi standard v1.2.4 is coming, fixed frequency voltage regulation scheme may benefit
Release time：2018-08-31Preview times：414Recently, the WPC wireless charging alliance released the latest Qi standard on its official website, version No. v1.2.4, which will be enforced on March 8, 2018, which means that the wireless charging products will need to be certified in accordance with Qi v1.2.4 standard, instead of Qi v1.2.3. With the release of Qi, the latest standard, constant frequency voltage regulation scheme may benefit.
Qi协议的主要变化
（Notes：BPP：Basic Power Profile，EPP：Extended Power Profile）
In terms of apple 7.5W transmitter authentication, compared with Qi v1.2.3, Qi v1.2.4 has the following updates:
The TX type mp-a11 is formally included in the Qi standard in Qi v1.2.4.
2. In the version of Qi v1.2.3, this kind of transmitter passes the BPP + FOD extensions certification. In the newly released version of Qi v1.2.4, the certification level of the transmitter is simplified and will pass the EPP (mp-a11) certification.
To sum up, after the new protocol is enforced, the type of Qi authentication that apple 7.5W transmitter needs to pass is EPP (mp-a11).
Interpretation of wireless charging transmitter scheme on the market
At present, wireless charging transmitters in the market are mainly divided into two categories:
The first type is the mid and low-end transmitter, which adopts frequency conversion architecture and constant frequency and duty cycle architecture.
The working principle of the frequency conversion architecture is to adjust the transmission power by changing the working frequency, which will cause certain interference to the mobile phone circuit in some transmission frequency bands. At present, the transmitter with up conversion structure in the market generally adopts a11 or a11a, and can only pass BPP certification. The power of these transmitters is generally more than 5W and less than 10W, without Q-value detection circuit, and the performance of FOD (metal foreign object detection) is significantly inferior to that of transmitters that have passed BPP + FOD extensions and EPP certification schemes.
On the basis of a11 / a11a, some transmitters support Apple's 7.5W fast charging by adjusting the duty cycle at a fixed working frequency.The transient response of this architecture is poor. Generally, the transmitter based on this architecture does not have Q value detection circuit, so it is poor in FOD detection, does not meet the EPP requirements, and cannot pass the EPP certification. As a kind of Chinese innovation, the fixed frequency and duty cycle architecture is superior to the high cost-effective scheme, and to a certain extent, it also allows users to enjoy the experience of Apple's fast charging at a lower price, but it cannot achieve zero interference to mobile phones.What's more, it doesn't conform to MFI specification, and it doesn't belong to one of the standard architectures of Qi. It may not meet the more stringent fast charging requirements of Apple mobile phone in the future, and it is more likely to fail to pass the apple certification in the future.
The second is the transmitter, which supports apple 7.5W, and adopts the constant frequency and voltage regulation architecture.
Constant frequency and voltage regulation is Apple's official standard scheme. The 7.5W fast charging proposed by Apple at the MFI conference uses the constant frequency and voltage regulation architecture. Mp-a11 topology is adopted, the working frequency is fixed at about 127khz, the duty cycle is constant at 50%, and the transmitting power is controlled by adjusting the voltage. It can effectively avoid the interference frequency band of mobile phone and minimize the interference of wireless charging to mobile phone. With Q value detection circuit, FOD detection will be more sensitive and meet the requirements of EPP. The scheme can pass BPP + FOD extensions and EPP authentication. After the implementation of WPC Qi v1.2.4, it belongs to EPP certification. The representatives of the manufacturers of the constant frequency and voltage regulation schemes on the market are NXP, IDT and CPS.
At present, apple 7.5W transmitter with large-scale modulus and constant frequency and voltage regulating structure is known on the market. In addition to mophie and Belkin officially recommended by apple, there are ravpower, spiegen, Anker, etc. NXP scheme is adopted for the first two, and CPS scheme is adopted for the last three. NXP, as the official supplier of Apple Wireless charger, is naturally the benchmark of constant frequency and voltage regulation scheme, of course, the cost will be higher.As a leading enterprise in the industry, Eason wireless is the most widely used 7.5W fixed frequency scheme product and also widely used in first-line brands. As for IDT, it is reported that it has also recently launched relevant products, and it is believed that the market will enter the next round of competition soon. At the same time, it is found that there is an updated second generation of mophie transmitter on the WPC official website certification product page. This transmitter is a constant frequency and voltage regulation architecture, which supports apple 7.5W fast charging. It is said that the solution provider is changed from NXP to easy to flush wireless.
How to choose brand manufacturers?
First of all, in terms of authentication, the wireless charging power of mobile phones on the market is generally higher than 5W, generally 7.5W or 10W, so the transmitter scheme needs to pass Qi v1.2.4 EPP authentication. The second is the scheme. Because we need to pay attention to the performance of charging stability, charging efficiency, FOD, interference with mobile phones, etc., Apple's 7.5W fast charging product is best to choose the fixed frequency and voltage transmitter scheme specified by apple.
Conclusion:
Apple's new phones are all equipped with wireless charging, which has completely exploded the market. Then LG, Nokia, Sony, Jinli, Xiaomi, Huawei and other manufacturers have or will follow up the technology, which is unstoppable. It can be expected that the release of Qi v1.2.4 will further standardize the wireless charging market and promote industrial upgrading. Apple's 7.5W wireless charging products will be equipped with mainstream constant frequency and voltage regulation schemes.
