GSWP050W-EVBPA
GaN E-HEMT Wireless Power Transfer Evaluation Board
User’s Guide
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GSWP050W-EVBPA Rev 190304
© 2019 GaN Systems Inc.
www.gansystems.com 9
Please refer to the Evaluation Board/Kit Important Notice on page 22
Circuit Description
The Push-Pull circuit is comprised of two single ended PAs which share a common supply, however;
the impedance matching is separated.
The high-side E-HEMTs are powered by a DC source, referred to as the HV supply. It is connected
through J32. The voltage of this source not exceed 25V
DC
.
The low-voltage logic circuitry runs off a 3.3V
DC
voltage regulator, U88, which is powered from a
+5V
DC
source connected through JP35. The +5V
DC
rail also feeds two PE29102 drivers U86 and U90,
which are driven independently by U87, a common logic D-type flip/flop. U87 has a frequency
divider configuration, which is driven by a crystal oscillator Y8 at a frequency of 13.56MHz. The
two PE29102 gate drives are capable of 6V operation.
The PA can be configured to operate in a number of different modes, which include
•
Push-pull configuration
•
Single ended mode
Detailed operation procedures and setup for these alternative configurations are provided in the
section titled “quick start guide”.
The PA includes an over-temperature protection circuit. Temperature sensor U9, placed close to the
GS61004B E-HEMTs, monitors their temperature. In an over-temperature condition, the PE29102A
driver will be disabled through U133 and stop driving the E-HEMTs. The design also includes
circuitry to protect against over-current, and load mismatch.
For convenience, test points are provided to monitor and measure the electrical signals. A
description of the test points and diagram of their location is provided in Table 4.
The PA also includes a Micro Controller Unit (MCU) monitor interface header, J1. The signals
available through J1 can be used to control the PA system for close loop in the WPT system. A
definition of the signals available on header J1 is provided in Figure 10.