Update to KDB 680106 on wireless power transfer (WPT) for FCC certification. In recent years smartphones have developed rapidly, with ever richer functions driving the WPT market, so that WPT has become a standard feature of smartphones. As well as launching dedicated WPT base products, manufacturers are also developing products that incorporate WPT base functions into desk lamps, desktop speakers and even power banks.

For short-range low-power WPT, the FCC issued KDB 680106 D01, whose current official version on the website is V03r01, to provide guidance for such products. The latest draft DR04 44611 was published on 18 February 2023, with comments collected until 20 March 2023 and version v04 published after that date.

On 24 October 2023 the FCC released the new wireless charging requirement KDB 680106 D01 Wireless Power Transfer v04, consolidating the guidance put forward at TCB workshops over the past two years, as detailed below.

Update 1

The FCC certification regulation for wireless chargers is FCC Part 15C §15.209, and the operating frequency of the product must fall within the range of Part 15C §15.205(a). That is, equipment authorised under Part 15 may not operate in the 90-110 kHz band. Besides meeting the regulatory requirements, products must also follow the conditions of KDB 680106.

Update 2

Under the new version of the KDB for wireless charging equipment published on 24 October 2023 (KDB 680106 D01 Wireless Power Transfer v04), an ECR (the pre-test lab inquiry) is required if the following conditions are not met. The applicant submits an enquiry to the FCC in accordance with the KDB guidance in order to obtain FCC authorisation.

However, exemption applies when the product meets all of the following conditions:

(1) The power transfer frequency is below 1 MHz;

(2) The output power of each transmitting element (for example a coil) is less than or equal to 15 W;

(3) The test periphery at maximum permitted load is in physical contact with the transmitter (that is, the surfaces of the transmitter and peripheral enclosures must be in direct contact);

(4) Only the §2.1091 mobile exposure conditions apply (that is, §2.1093 portable exposure conditions are not covered);

(5) The RF exposure test results must comply with the limits;

(6) For devices with more than one charging structure, for example a device that may use three 5 W coils or one 15 W coil, both states must be tested and both results must satisfy condition (5).

If any one of the above is not met, an ECR is required. In other words, if the wireless charger is a portable device, the ECR route must be followed and the following information provided:

The operating frequency of the WPT

The power of each WPT coil

Demonstration of the operating scenario for mobile or portable devices, including RF exposure compliance information

The maximum distance from the WPT transmitter

Update 3

Requirements are defined for WPT devices with a transmission distance of 1 m or less and greater than 1 m.

A. WPT transmission distance of 1 m or less and compliant with this KDB: no KDB enquiry needs to be submitted.

B. WPT transmission distance of 1 m or less but not compliant with this KDB: a KDB enquiry must be submitted to the FCC to obtain authorisation.

C. WPT transmission distance greater than 1 m: a KDB enquiry must be submitted to the FCC to obtain authorisation.

Update 4

When WPT wireless charging equipment is authorised under FCC Part 18 or Part 15C, whether through the FCC SDoC or FCC ID Certification procedure, a KDB enquiry must be submitted to the FCC and only becomes a valid authorisation once approved.

Interpretation of FCC KDB 680106

KDB 680106 D01 DR04 44611 sets out the requirements for short-range low-power wireless inductive charging pads or charging equipment.

Scope

KDB 680106 D01 mainly provides guidance for low-power, closely coupled inductive power transfer technology. For other equipment such as high-power and long-distance power transfer devices and medical devices, manufacturers may need to submit a case-by-case KDB enquiry (http://www.fcc.gov/labhelp) to the FCC for guidance on specific WPT devices. (Note: the KDB enquiry should include the following.)

A complete product description, including coil diameter, number of turns and current;

The FCC Part rules under which the device will operate and the basis for choosing them;

The planned equipment authorisation procedure (that is, SDoC or certification);

Drawings and illustrations, operating frequency, radiated power, operating configuration and human exposure conditions.

Applicable regulations

WPT devices can operate in two different modes: charging and communication.

(1) WPT products with charging function only need to comply with the relevant FCC Part 18 rules;

(2) WPT products with both charging and communication functions must comply not only with FCC Part 18 but also with the relevant FCC Part 15 rules.

Operating bands

All WPT operating at frequencies above 9 kHz must comply with the FCC rules, and WPT devices authorised under FCC Part 15 may not transmit in the 90-110 kHz band.

RF exposure

RF exposure applies to WPT devices. Whether FCC Part 15 or FCC Part 18 is used, the RF exposure requirements must be met.