EPC9112(#2): 35W, Class 3, Rezence (A4WP) Compatible

The EPC9112 wireless power demonstration system is a high efficiency, A4WP compatible, Zero Voltage Switching (ZVS), Voltage Mode class-D wireless power transfer demonstration kit capable of delivering up to 35 W into a DC load while operating at 6.78 MHz (Lowest ISM band).

The purpose of this demonstration system is to simplify the evaluation process of wireless power technology using eGaN® FETs.

The EPC9112 wireless power system comprises the three boards (shown in Figure 1) namely:

• 1) A Source Board (Transmitter or Power Amplifier) EPC9507
  

• 2) A Class 3 A4WP compliant Source Coil (Transmit Coil)
  

• 3) A Category 3 A4WP compliant Device Coil with rectifier and DC smoothing capacitor.

The amplifier board features the EPC2007C and EPC2038 enhancement mode field effect transistors (FET) in an optional half-bridge topology (single ended configuration) or default full-bridge topology (differential configuration), and includes the gate driver/s and oscillator that ensures operation of the system at 6.78 MHz. This revision of the wireless demonstration amplifier includes a synchronous bootstrap FET supply for the upper FETs of the ZVS class-D amplifier that eliminates the reverse recovery losses of the gate driver’s internal bootstrap diode that dissipates energy in the upper FET. This circuit has been implemented using the new EPC2038 eGaN FET specifically designed for this function. To learn more about the synchronous bootstrap supply please refer to the following [1, 2, 3]. The EPC9507 amplifier board can also be operated using an external oscillator or by using the included new ultra low power Diashinku oscillator.

This revision can operate in either Single ended or Differential mode by changing a jumper setting. This allows for high efficiency operation with load impedance ranges that allow for single ended operation.

Finally, the timing adjust circuits for the ZVS class-D amplifiers have been separated to further ensure highest possible efficiency setting and includes separate ZVS tank circuits.