Qi 1.3 Wireless Charging Standard

On August 23, 2021, the Wireless Power Consortium (WPC) announced the release of Qi v1.3, the latest version of its Qi (pronounced “chee”) wireless charging specification for smartphones and small mobile devices. It follows Qi 1.2.4. The Qi v1.3 standard adds new authentication features that include improvements in compliance testing (reduce development costs) and reducing the false positives in Foreign Object Detection (FOD) to ensure better interoperability, a safer and more reliable wireless charging experience.

“With more than 100 new Qi products certified every month, it’s important to make it easier to develop wireless charging products that are safe at high power levels and easy to use,” said Menno Treffers, Executive Director and CEO at Wireless Power Consortium. “These new features and improvements keep both these factors at the core of the Qi standard. Qi v1.3 allows us to ensure that increases in power levels do not come at the cost of consumer or device safety.”

Key Features of Qi V1.3 Standard: 

Authentication

When a Qi-certified receiver (smartphone) is placed on/near the charger pad, it will send a short communication protocol to request a certification key from the transmitter (charger). The receiver uses a pre-defined algorithm to check whether the transmitter is Qi-certified or not. If the transmitter is Qi-certified, then the receiver will request the desired amount of charging power from the transmitter to ensure safe charging.  

The authentication features of the Qi v1.3 standard enables devices to check whether a charger is Qi Certified and allows them to reduce the speed of charging if the charger is not Qi-certified (i.e., the mobile phone reduces the speed of charging when the charger has old Qi specification (like Qi v1.2)).

Compliance Testing Improvements Reduce Development Costs

As the number of Qi Certified wireless products rapidly increases, interoperability testing is essential to ensure a reliable and consistent user experience when using the products and brands. The new Qi v1.3 standard adds improvements in Qi compliance testing; for example, the addition of new test cases and automation of time-consuming sections of the overall testing process (saves time). These new changes help the manufacturer to design interoperable products easily, reducing the chances of last-stage design changes and generally reducing the product development costs & time.

Reducing False Positives in Foreign Object Detection

Qi Certified wireless products have been tested for compliance with Qi safety features. An important part of the Qi standard is foreign object detection (FOD). When metal objects like coins, credit cards, keys, cords, etc., are placed on Qi Certified wireless chargers, the charger detects these foreign objects and does not transfer power. This action helps to prevent overheating/unnecessary power transfer or other damages or safety risks.

The Qi v1.3 standard adds methods that increase the sensitivity of foreign object detection (FOD) and reduce the probability of false positives. These methods include the improvements in the power loss calculation method, a pre-power transmission method, and an improved description for Q-value based FOD method to ensure the sensitivity of FOD.

Hence, the updated Qi v1.3 standard helps to ensure safety while maintaining a consistent and positive user experience.

Will the Qi v1.3 Certified products be backward compatible with old specifications?

The new authentication protocol will use the physical components (integrated chip) which are not in present devices that support the Qi standard v1.2. The Qi v1.2 certified devices will not become outdated overnight but may encounter some limitations in the future based on the combination of devices being used.

• v1.3 charger and v1.3 smartphone: Following the successful authentication process, optimal charging output will be provided. 
• v1.3 charger and v1.2 smartphone: The receiver (smartphone) sends a request on how much power it needs. If the receiver does not support the authentication feature, the receiver may receive limited charging power from the transmitter. It depends on the manufacturer's policy for un-authenticated devices.
• v1.2 charger and v1.2 smartphone: Continue to operate as normal when used together.

Importance of Qi Specifications

The Qi wireless charging specification/standard has been developed and is promoted by the WPC to create interoperability between the Qi-Certified power transmitter (mobile charger/charging station) and power receiver (smartphones/portable device). This WPC standard describes the type of inductive coupling (coil configuration) and the communications protocol to be used for Qi-Certified wireless devices that use inductive coupling for power transfer. Phone companies that support the Qi standard include Apple, Sony, Xiaomi, and Sharp Corporation.

Qi-certified wireless products have the Qi logo on them, and the Qi certification is only provided for the products of WPC member companies. While wireless power transferring, the device authentication between the Qi-certified devices relies on physical chipsets integrated into both certified transmitters and receivers (meaning that authentication is not possible by firmware update). These special authentication chips are produced and supplied by a limited no of manufacturers who are the approved partners of WPC. Thus, it is difficult for manufactures to make counterfeit chips or falsely claim their products are certified.

Wireless chargers which have not passed Qi certification may not support or comply with essential safety features lead to damage to the receiver devices or harm the users or dangerous incidents such as fire. Hence, the Qi-certified products have a number of safety features to minimize the risk of damage to users and their devices and to ensure a safe reliable wireless charging experience. So, the main aim of Qi certification/standard is the safe and reliable positive wireless charging experience of the users.  

Wireless Power Consortium

WPC (Wireless Power Consortium) is a worldwide organization, a group of more than 400 member companies that include diverse industries, electronics manufacturers, and original equipment manufacturers (OEMs). The WPC was established in 2008.

The aim of the WPC is to develop and promote global standards for wireless power transfer in various application areas to ensure consumer & device safety and a more reliable positive wireless charging experience. The WPC standard describes the type of inductive coupling (coil configuration) and the communications protocol to be used for wireless devices that use inductive coupling for power transfer.

The WPC develops and promotes Qi standards for smartphones and other portable mobile devices (can transmit and receive power up to 15 W). In the future, Qi standard for power delivering up to 60W to enable laptop charging and other portable devices. 

The other WPC standards for wireless power transfer include the Ki Cordless kitchen standard (for delivering up to 2,200W to Cordless Appliances), Light Electric Vehicle (LEV) standard (for charging e-bikes and e-scooters), and Industrial standard (for safe and convenient charging of robots and other industrial automation).