Wideband Class E power amplifier with the reactance compensation network.

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... P is the output power, ω is the angular frequency, and Q S is the quality factor of the L S C S series filter. In the wideband Class E power amplifier, we add an additional L P C P resonant tank at the output (shown in Fig. 1) to include the reactance compensation feature. The goal is to maintain high efficiency and deliver the same output power across a wide band, which requires the power amplifier to operate under ZVS and have a constant drain impedance in the entire ...

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... of 13.56 MHz with a bandwidth of ±1 MHz. Designing a kW power amplifier often requires more than one power stage due to the switching devices' thermal limit, the magnetic cores' saturation constraints, and other component ratings. In this work, we connect two identical wideband Class E power amplifiers in parallel with each outputting 500 W. Fig. 10 and Fig. 11 show the schematic and PCB of the design. The SiC MOSFET used in the design (G3R350MT12 J) has low gate charge (10 nC) and low gate resistance (2.5 ), making it suitable to switch at 13.56 MHz. In the power amplifier, L F is a hand-wound air-core inductor; L S and L P use material 67 from Fair-Rite because of its highest ...

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... MHz with a bandwidth of ±1 MHz. Designing a kW power amplifier often requires more than one power stage due to the switching devices' thermal limit, the magnetic cores' saturation constraints, and other component ratings. In this work, we connect two identical wideband Class E power amplifiers in parallel with each outputting 500 W. Fig. 10 and Fig. 11 show the schematic and PCB of the design. The SiC MOSFET used in the design (G3R350MT12 J) has low gate charge (10 nC) and low gate resistance (2.5 ), making it suitable to switch at 13.56 MHz. In the power amplifier, L F is a hand-wound air-core inductor; L S and L P use material 67 from Fair-Rite because of its highest performance ...

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... F is a hand-wound air-core inductor; L S and L P use material 67 from Fair-Rite because of its highest performance factor around 10 MHz [35]. In the gate drive circuit, we use the air-core inductors from Coilcraft for L f , L m1 , and L m2 , and hand wind L s . Table 3 lists the component values and part numbers of the devices used in the design. Fig. 12 shows the measured drain impedances at nodes V d1 and V d2 in Fig. 10 after tuning. The parallel-connected power amplifiers have matched and relatively flat drain impedances within the bandwidth of 12.56 MHz to 14.56 MHz. Fig. 13 shows the measured drain voltages (V d1 , V d2 ) and gate voltages (V g ) in the power amplifier (Fig. 10), ...

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... Fair-Rite because of its highest performance factor around 10 MHz [35]. In the gate drive circuit, we use the air-core inductors from Coilcraft for L f , L m1 , and L m2 , and hand wind L s . Table 3 lists the component values and part numbers of the devices used in the design. Fig. 12 shows the measured drain impedances at nodes V d1 and V d2 in Fig. 10 after tuning. The parallel-connected power amplifiers have matched and relatively flat drain impedances within the bandwidth of 12.56 MHz to 14.56 MHz. Fig. 13 shows the measured drain voltages (V d1 , V d2 ) and gate voltages (V g ) in the power amplifier (Fig. 10), and the drain voltages of the switching device in the gate drive ...

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... and L m2 , and hand wind L s . Table 3 lists the component values and part numbers of the devices used in the design. Fig. 12 shows the measured drain impedances at nodes V d1 and V d2 in Fig. 10 after tuning. The parallel-connected power amplifiers have matched and relatively flat drain impedances within the bandwidth of 12.56 MHz to 14.56 MHz. Fig. 13 shows the measured drain voltages (V d1 , V d2 ) and gate voltages (V g ) in the power amplifier (Fig. 10), and the drain voltages of the switching device in the gate drive circuit (V d,Sg in Fig. 4) at 12.56 MHz, 13.56 MHz and 14.56 MHz. At all frequencies, the drain voltages in the parallel-connected Class E power amplifiers reach ...

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... the design. Fig. 12 shows the measured drain impedances at nodes V d1 and V d2 in Fig. 10 after tuning. The parallel-connected power amplifiers have matched and relatively flat drain impedances within the bandwidth of 12.56 MHz to 14.56 MHz. Fig. 13 shows the measured drain voltages (V d1 , V d2 ) and gate voltages (V g ) in the power amplifier (Fig. 10), and the drain voltages of the switching device in the gate drive circuit (V d,Sg in Fig. 4) at 12.56 MHz, 13.56 MHz and 14.56 MHz. At all frequencies, the drain voltages in the parallel-connected Class E power amplifiers reach zero before the gates of the SiC MOSFETs turn on, demonstrating ZVS behaviors. Due to probes' derating at ...

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... drain node and the probe. The actual maximum drain voltages are around 800 V in all cases. We use a GaN HEMT as the switching device in the gate drive circuit since its low gate charge makes it easy to drive at MHz frequencies. The drain voltage waveforms of the GaN HEMT at all three frequencies also demonstrate operations under or close-to ZVS. Fig. 14 shows the measured gate power at 12.56 MHz, 13.56 MHz, and 14.56 MHz. The red bars show the gate power in driving the GaN HEMT at three frequencies, which ranges from 0.35 W to 0.4 W. The gray bars show the power dissipated in the rest of the gate drive circuit from the DC input source. With a rising time of 10 ns, the total gate power ...

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... power in driving the GaN HEMT at three frequencies, which ranges from 0.35 W to 0.4 W. The gray bars show the power dissipated in the rest of the gate drive circuit from the DC input source. With a rising time of 10 ns, the total gate power to drive both SiC MOSFETs (shown in the blue line) is between 2.95 W to 3.1 W across the 2 MHz bandwidth. Fig. 15 shows the total output power and efficiency of the design presented. The wideband Class E power amplifier achieves a total efficiency of 93% to 94% and maintains the output power with less than 10% variation within the bandwidth of 12.56 MHz to 14.56 MHz. Fig. 16 shows the loss breakdown of the design. 70% of the power losses come from ...

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... (shown in the blue line) is between 2.95 W to 3.1 W across the 2 MHz bandwidth. Fig. 15 shows the total output power and efficiency of the design presented. The wideband Class E power amplifier achieves a total efficiency of 93% to 94% and maintains the output power with less than 10% variation within the bandwidth of 12.56 MHz to 14.56 MHz. Fig. 16 shows the loss breakdown of the design. 70% of the power losses come from the two SiC MOSFETs, mainly consisting of MOSFETs' conduction losses and C oss losses [36]. Core and winding losses from all inductors add to a total of 17%, and the custom gate drive circuit consumes another 5%. Other losses include the losses in the capacitors, ...