GSWP300W-EVBPA
GaN E-HEMT Wireless Power Transfer Evaluation Board
Technical Manual
_____________________________________________________________________________________________________________________
GSWP300W-EVBPA Rev 220215
© 2022 GaN Systems Inc.
www.gansystems.com 11
Please refer to the Evaluation Board/Kit Important Notice on page 27
R177. Upon an over current event, a signal is generated to signal OCP_TRIG.
Overvoltage protection (OVP): The design includes overvoltage protection circuitry for both the
high side and the low side. The high side voltage sensor is comprised of C276, C277, and two
Schottky diodes; D52 and D44. C276/C277 form a voltage divider, the ratio of which can be
changed. Two diodes rectify the RF signal to DC thru C278/C22 and R111 and the resulting voltage
represents the high side output. The low side circuit
is similar. It’s comprised of
C270, C280, and
two diode D50, D53. These two voltage detection signals go to a two-channel comparator U68 and
are combined with OR gate U70 into one overvoltage trigger, OVP_TRIG.
The OVP and OCP go into a hard combine circuit D45, which a dual diode in one. To generate an
overcurrent / overvoltage protection trigger signal.
Standing Wave Ratio (SWR) detection: two of coupler, T2, T83, comprise of the board band
bidirectional coupler. The reflection signal goes thru D75, C722, C721, it turns into DC signal which
goes thru the buffer OP U132 into comparator U130, of which the reference voltage is set by the
R936/R937, the trigger point can be set by the reference voltage, which is refer the SWR. The
direction of the coupler is around 15dB at 6.78MHz.
Figure 11 •
Connectivity locations
Thermal Management
Thermal management of the GaN E-HEMTs in this RF power system is a critical aspect of the
J56
RF output before EMI filter
J28
HV DC Input
J31 & J33
RF output before EMI
Single ended
J1
MCU interface
J57
RF Out
Push pull SMA
pSemi
PE29102A
GaN Systems
GS66508B
J34
SMA external input
J32
HV DC Input
