GSWP050W-EVBPA
GaN E-HEMT Wireless Power Transfer Evaluation Board
User’s Guide
_____________________________________________________________________________________________________________________
GSWP050W-EVBPA Rev 190304
© 2019 GaN Systems Inc.
www.gansystems.com 19
Please refer to the Evaluation Board/Kit Important Notice on page 22
Figure 20 •
Output power and efficiency of PA at JP57 SMA
The PA’s system reliability is optimized when the temperature rise of each device is kept to a minimum,
including that of the GaN E-HEMTs. The GS61004Bs are especially well suited in this regard, for a
number of reasons. First, they have very low switching losses which allows them to operate at high
efficiency and a low temperature rise at 6.78MHz, the common frequency used for resonant wireless
power transfer. Secondly, the bottom-side cooled GaN
PX
® packaging provides an extremely low
thermal impedance for efficient heat transfer to the heatsink, thereby drawing heat out of the device.
This GaN based design is able to operate over a wide ambient temperature and with convection cooling,
eliminating the need for cooling fans. These advantages support a PA design with excellent thermal
performance up to 50W output power.
The temperature plot of the PA design was measured and captured with a SEEK thermal camera and is
shown in Figure 21. The hottest devices are the first inductors, with the hottest inductor recording 40
˚C
above ambient. The temperature rise of the GaN E-HEMTs, by comparison, is only 7
˚C. Because the
GaN E-HEMTs run very cool, this allows operation over a very wide temperature range and extends
operation to a higher power level while simultaneously simplifying the cooling system design and
reducing the cost.
50.0%
55.0%
60.0%
65.0%
70.0%
75.0%
80.0%
85.0%
90.0%
95.0%
0.00
10.00
20.00
30.00
40.00
50.00
60.00
5
10
15
20
25
30
Eff(
%)
Po
ut(
W
)
Vin(V)
50W WPT PA Pout(W) & Efficiency(%)
Power(W)
Eff(%)