After the three new Apple phones were equipped with wireless charging functions in September 2017, wireless charging has become a must-have feature for handset manufacturers in 2018. On March 27th, Xiaomi and Huawei chose to release the new machine on the same day. Xiaomi used wireless charging on the MIX 2S, while Huawei chose wireless charging on the Porsche version of the P20. In addition to mobile phones, both manufacturers have released their own brands of wireless charging transmitters. According to the latest data from Wireless Power Consortium (WPC), WPC already has 512 members, and more than 60 mobile phone models have passed Qi authentication. Products that pass Qi certification include transmitters (TX) and receivers (RX). ) has exceeded 1,245 models
This article will focus on the current Q1 certification that the wireless charging industry and vendors are very concerned about, and interpret in detail the certification projects, processes and common problems under the new WPC regulations.
WPC began implementing the new V1.2.4 Qi certification standard in March 2018. All certified products are divided into BPP (Baseline Power Profile) and EPP (Extended Power Profile) types according to the load power. BPP covers products with output power less than or equal to 5W; EPP includes products with more than 5W up to 30W. Because EPP is for Medium Power product certification, strictly speaking, all current Apple fast charge 7.5W and 10W Samsung Fast Charging should be within the scope of EPP certification.
Whether it is BPP or EPP, Qi's certification testing process includes two parts. The first is the Compliance Test and the second is the Qi Interoperability Test. The ATL (Authorized Test Lab) has many options in the country. The compatibility test laboratory IOC (Interoperability Test Center) has only two worldwide, one in Belgium in Europe, and the second in South Korea.
For the universally concerned wireless charging transmitter, the process of Qi certification testing is as follows:
1) Compliance testing. Sending and testing parties need to send at least 5 prototypes to be tested. One of them will be arranged to conduct compliance testing first. Conformance test samples will remain in the ATL after the test passes.
The main test content includes
- Timing of communication protocol between transmitter and receiver
- Test power output capability by translation of the XYZ axis
— Maximum supply capacity for energy transmission
— Foreign Object Detection (FOD)
2) Compatibility testing. After passing the conformance test, ATL will divide the other four units in the test prototype into two groups and send them to the laboratories in Belgium and South Korea for compatibility testing. Two samples were left in the main IOC laboratory and the other two were left in the auxiliary IOC laboratory. After the main IOC laboratory receives the sample sent by ATL, it will start compatibility testing. After the compatibility test is completed, the inspection party can execute the “Confirmation Completed” action on the official website. The product can be included on the WPC website and the product will be retained on the Test Bed. The current Test bed has about four hundred transmitters and one hundred receivers.
According to WPC requirements, all test samples need to be tested for compatibility with all previously certified samples. If the product being tested is a wireless charging transmitter, then it is required to do compatibility testing with all WPC-qualified receivers.
The compatibility test includes two aspects. First, when the transmitter and the receiver are put together, both need to establish communication within 3 seconds. Second, in the case of testing the battery power of the product from 10% to 20%, it is necessary to maintain the charge for five minutes.
According to the requirements of the WPC process, great care must be taken when testing for compatibility. According to Qi's test procedure, the tested product is sent to the compatibility test after the compliance test passes. If the compatibility test fails, the sample needs to be brought back for rectification. After the rectification, it can not be directly sent to the compatibility test, but it needs to go through the conformance test + compatibility test process again.
According to the conventional test cycle calculation, if there is no failed project for a test product, the time required to pass all test items at one time is 4-5 weeks. According to WPC data, in November of the 2017 certification peak period, for example, a total of nearly 30% of the tested products failed to pass the first compatibility test, while the EPP test sample, the first time the failure rate was as high as 61.5%; Even if it is currently more common BPP test, there is still close to 20% failure rate.
For such a high test failure rate, the author summarizes the most common problems:
1) The CE (Control Error) packet jumped out of -1,0,+1 during sample operation
2) ASK or FSK connection is interrupted before and during power transfer
3) FOD detection disorder
4) Transmitters and receivers In the process of establishing the communication process, there is a phase of the Qi protocol handshake, because the error in the data packet sending mode causes the two parties to fail to connect effectively.
5) The transmitter is very sensitive to the location of the test receiver and can only support certain positions.
6) When the transmitting transmitter supports multiple fast charging protocols, such as 10W Samsung Fast Charge (SFC) and 7.5W Apple fast charge, the transmitter is prone to protocol disorder during the Qi certification test. It cannot work properly with the test receptor.
The author summarized the laboratory data in Shenzhen, combined with the issues listed above, the current difficulties in Qi authentication of wireless charging transmitters concentrate on the following points:
1) Item 23 (Maximum Energy Supply Test)
2) Item 25: FOD foreign body detection
3) Tests with many receivers in compatibility tests are prone to failures (after rectification, a complete two-step testing process is required)
According to the laboratory's statistics, Jinxin Micro always maintains a 100% one-time wireless charging solution in all submitted Qi certifications. Under the increasingly stringent new WPC regulations, it is possible to maintain such a high certification pass rate, thanks to Jinxin Micro's focus on R&D in the field of wireless charging in recent years. The leading edge of the design concept makes the product design of the solution able to quickly adapt to the changes and development of Qi certification. In terms of product stability, compatibility and standard adaptability, it fully meets or exceeds the WPC requirements.
Combined with WPC official website data and laboratory data sources, Jinxin Micro currently has several leading projects in Q certification.
1) MP-A6 EPP certification for the world's first triple coil
2) The world's second MP-A11 EPP certification based on the Apple A11 coil design (the vast majority of EPPs are based on MP-A2 or A6 coils, certification requirements are much lower than Apple's A11), the first is NXP's Module (certificate is much harder than finished product)
3) EPP certification of MP-A11, the world's first Qi new specification 1.2.4
4) First to introduce the dual FOD detection standard, which was later included by the WPC in the Qi certification specification
Qi certification is a double challenge to the wireless charging industry for the cost and technology of manufacturers and brands, but it also represents a huge opportunity for outstanding manufacturers and solutions. If our domestic manufacturers are able to face international standards actively and even require their own design standards to exceed international standards, they will undoubtedly become market leaders.