Efficient Power Conversion Corporation (EPC) of El Segundo, California USA, made available a complete class 4 wireless power kit, the EPC9129. The company intends the demonstration kit to simplify the evaluation of using eGaN FETs for highly efficient wireless power transfer. According to EPC, the system can transmit up to 33 W while operating at 6.78 MHz (the lowest ISM band). The kit comes complete with two receivers. Each delivers a regulated output. One of the receivers can transmit 5 W of power and the second can deliver 27 W at 19 V.
The EPC9129 uses the high-frequency switching of the EPC gallium-nitride transistors to enable wireless power systems with full power efficiency ranging from 80% to 90% under various operating conditions.
The EPC9129 wireless power system consists of four boards:
- Source Board (Transmitter or Power Amplifier) EPC9512 features the EPC8010, EPC2038 and EPC2019
- Class 4 Air Fuel compliant Source Coil (Transmit Coil)
- Category 5 AirFuel compatible Receive Device EPC9514 featuring the EPC2016C
- Category 3 AirFuel compatible Receive Device EPC9513 featuring the EPC2019
The company notes that popularity of highly resonant wireless power with large power transmitting surface areas is increasing rapidly. These large surface areas let users place multiple receiving devices anywhere on the surface for simultaneous charging.
Source (Amplifier) Board
The source board offers highly efficient Zero Voltage Switching (ZVS) and a Class-D amplifier configured in either a half-bridge topology (for single-ended configuration) or the default full-bridge topology (for another configuration).
The source board also includes the gate driver(s), oscillator, and feedback controller for the pre-regulator, thereby, allowing compliance testing for the AirFuel class 4 standard over a wide load range.
The amplifier board is available separately as EPC9512 for evaluation in existing customer systems.
Device (Receiving) Boards
The Category 5 EPC9514 (19 V, 27 W) and Category 3 EPC9513 (5 V, 5 W) device or receiving boards included in the wireless power demonstration kits are also available separately for customers with their own source boards or those who want to operate multiple receiving devices simultaneously. The end-to-end efficiency of these first-generation systems is about 87%. EPC contends that with future improvements in architecture and GaN IC technology, this efficiency could reach the 95% range.