EPC Introduces a 33 Watt Wireless Power Charging Kit

Efficient Power Conversion Corporation (EPC) has announced the availability of a complete class 4 AirFuel Alliance compatible wireless power charging kit, the EPC9120. The system can transmit up to 33 Watts of power while operating at 6.78 MHz (the lowest ISM band). The purpose of this demonstration kit is to simplify the evaluation process of using eGaN FETs for highly efficient wireless power transfer. The EPC9120 utilizes the high frequency switching capability of EPC gallium nitride transistors to facilitate wireless power systems with full power efficiency between 80% and 90% under various operating conditions.

The EPC9120 wireless power system consists of four boards:

  • Source Board (Transmitter or Power Amplifier) EPC9512
  • Class 4 AirFuel compliant Source Coil (Transmit Coil)
  • Category 4 AirFuel compliant Device Coil with rectifier and DC smoothing capacitor
  • Category 3 AirFuel compliant Device Coil with rectifier and DC smoothing capacitor.

The popularity of highly resonant wireless power transfer is increasing rapidly, particularly for applications targeting portable device charging. The end applications are varied and evolving quickly from cell phone charging, to handheld tablets, and laptop computers. Delivering 33 W of wireless power is a game changer, as it can be used to charge all these devices.

The source board is a highly efficient Zero Voltage Switching (ZVS), Class-D amplifier configured in an optional half-bridge topology (for single-ended configuration) or default full-bridge topology (for differential configuration), and includes the gate driver(s), oscillator, and feedback controller for the pre-regulator. This allows for compliance testing operating to the AirFuel class 4 standard over a wide load range.

This amplifier board is available separately as EPC9512 for evaluation in existing customer systems.

The source coil, as well as the device coil, are AirFuel compliant and have been pre-tuned to operate at 6.78 MHz. The source coil is class 4 and the device coils are category 3 and category 4 compliant. Both are available for immediate delivery from Digi-Key.