Introduction

The Wireless Power Consortium (WPC) is the global organization responsible for developing and maintaining the Qi wireless charging standard. Its scope includes standalone transmitters and receivers, as well as solutions integrated into consumer, industrial and automotive markets. The WPC defines specifications for Qi transmitters and receivers, develops compliance test procedures, and certifies products through accredited laboratories to ensure adherence to stringent Qi requirements. In addition, the WPC monitors products released to the field to ensure ongoing compliance with the standard.

Early versions of the Qi standard (versions 1.0 and 1.1) supported charging up to 5W, now referred to as the Baseline Power Profile (BPP). In 2015, the WPC introduced the Qi 1.2 Extended Power Profile (EPP), which enabled charging up to 15W but did not require authentication. Without authentication, receivers could accept higher power levels from non-certified chargers, potentially leading to device damage. To address this risk, the WPC released the Qi 1.3 standard in 2021, which mandates one-way, hardware-based authentication to verify that a charger has been tested and approved by the WPC and its accredited test labs. Under the Qi 1.3 standard, when a receiver—such as a smartphone—is placed on a compliant transmitter, it initially accepts a 5W charge. After successful X.509-based ECC asymmetric authentication confirms that the charger is an approved "do no harm" device, the receiver can safely accept power above 5W, up to a maximum of 15W, depending on device capability. To support this security model, the WPC has established a Root Certificate Authority (CA) and requires that all transmitters supporting Q1 1.3 EPP incorporate a Secure Storage Subsystem (SSS) that meets WPC-defined requirements. All Qi-certified authenticated transmitters must have their manufacturing CAs signed by the WPC Root CA.

Microchip Technology Inc. is a long-standing member of the WPC and actively contributes to the development of reference designs for power transmitters and receivers. Microchip is also a recognized leader in security technologies, offering secure devices and provisioning services. Leveraging this expertise, Microchip played an active role on the WPC committees that developed the Qi authentication specification and now supports the market with a range of hardware products and services.

The TA100 is a hardware-based SSS that meets the Qi authentication requirements for automotive transmitters. The remainder of this document outlines the relevant WPC requirements and describes how Microchip’s secure provisioning capabilities, together with the TA100, can be used to meet those requirements.