GaN EZ Drive GS65011-EVBEZ User manual

GS65011-EVBEZ
EZDrive®Open Loop Boost Evaluation Board
Technical Manual
_____________________________________________________________________________________________________________________
GSWPT-EVBEZ Rev. 210307 © 2021 GaN Systems Inc. www.gansystems.com 1
Please refer to the Evaluation Board/Kit Important Notice on page 17
GS65011-EVBEZ
GaN E-HEMT EZ Drive®Open Loop Boost
Evaluation Board
Technical Manual
Visit www.gansystems.com for the latest version of this technical manual.

GS65011-EVBEZ
EZDrive®Open Loop Boost Evaluation Board
Technical Manual
_____________________________________________________________________________________________________________________
GSWPT-EVBEZ Rev. 210307 © 2021 GaN Systems Inc. www.gansystems.com 2
Please refer to the Evaluation Board/Kit Important Notice on page 17
DANGER!
Electrical Shock Hazard - Hazardous high voltage may be present on the board
during the test and even brief contact during operation may result in severe injury
or death. Follow all locally approved safety procedures when working around
high voltage.
Never leave the board operating unattended. After it is de-energized, always wait
until all capacitors are discharged before touching the board.
This board should be handled by qualified personnel ONLY.
PCB surface can become hot. Contact may cause burns. Do not touch!
CAUTION:
This product contains parts that are susceptible to damage by electrostatic
discharge (ESD) or exposure to voltages in excess of the specified voltage. Always
follow ESD prevention procedures when handling the product. Avoid applying
excessive voltages to the power supply terminals or signal inputs or outputs

GS65011-EVBEZ
EZDrive®Open Loop Boost Evaluation Board
Technical Manual
_____________________________________________________________________________________________________________________
GSWPT-EVBEZ Rev. 210307 © 2021 GaN Systems Inc. www.gansystems.com 3
Please refer to the Evaluation Board/Kit Important Notice on page 17
Introduction
The GS65011-EVBEZ Evaluation Board (EVB) is an open loop Boost converter and was
designed to help customers evaluate GaN Systems’ EZDrive®solution with a GaN
Systems’ E-HEMT.
The EZDrive® circuit is a low-cost, easy way to implement a GaN driving circuit using a
standard MOSFET controller with integrated driver. The EZDrive®circuit provides
design control for the optimization of efficiency and EMI. It is adaptable to any power
level, any frequency, and any LLC and PFC controller.
The board is populated with GaN Systems’ GS-065-011-1-L, a 5×6 mm PDFN package
Enhancement-Mode High Electron Mobility Transistor (E-HEMT).
Evaluation Board Contents and Requirements
Kit Contents
The GS65011-EVBEZ includes the following hardware.
Table 1 • GS65011-EVBEZ Evaluation Kit Contents
Quantity
Description
1 GS65011-EVBEZ GaN E-HEMT evaluation board assembly
Hardware Requirements
In order to evaluate the performance of the evaluation board, the following equipment is required:
• High speed digital oscilloscope
• DC load (power resistor or electrical load)
• High voltage DC power supply
• Low voltage DC power supply
• DC test leads

GS65011-EVBEZ
EZDrive®Open Loop Boost Evaluation Board
Technical Manual
_____________________________________________________________________________________________________________________
GSWPT-EVBEZ Rev. 210307 © 2021 GaN Systems Inc. www.gansystems.com 4
Please refer to the Evaluation Board/Kit Important Notice on page 17
Evaluation Board Assembly Overview
The EVB is assembled with the EZDrive®circuit and one GS-065-011-1-L GaN E-HEMT.
Headers are included for power connections. A probe connecter and vias are included for
waveform measurements.
Figure 1 • GS65011-EVBEZ Evaluation Board Assembly

GS65011-EVBEZ
EZDrive®Open Loop Boost Evaluation Board
Technical Manual
_____________________________________________________________________________________________________________________
GSWPT-EVBEZ Rev. 210307 © 2021 GaN Systems Inc. www.gansystems.com 5
Please refer to the Evaluation Board/Kit Important Notice on page 17
Block Diagram and Schematic
The block diagram and schematic of the evaluation board are provided in Figures 2 and 3.
Figure 2 • GS65011-EVBEZ Block Diagram
V
CC
R
G2
5~12V
R
EZ2
C
EZ2
ZD
EZ2
ZD
EZ4
GS-065-
011-1-L
D
OFF2
R
OFF2
GND
GND
Vin
PWM CONTROL
CIRCUIT
Vout
L
EZDrive
TM
0~200V
0~400V

GS65011-EVBEZ
EZDrive®Open Loop Boost Evaluation Board
Technical Manual
_____________________________________________________________________________________________________________________
GSWPT-EVBEZ Rev. 210307 © 2021 GaN Systems Inc. www.gansystems.com 6
Please refer to the Evaluation Board/Kit Important Notice on page 17
Figure 3 • GS65011-EVBEZ Schematic

GS65011-EVBEZ
EZDrive®Open Loop Boost Evaluation Board
Technical Manual
_____________________________________________________________________________________________________________________
GSWPT-EVBEZ Rev. 210307 © 2021 GaN Systems Inc. www.gansystems.com 7
Please refer to the Evaluation Board/Kit Important Notice on page 17
Circuit Description
The GS65011-EVBEZ EVB is a GaN-based open-loop DC/DC Boost converter. It is
assembled with the EZDrive®GaN driving circuit, a Si MOSFET PWM controller
(TL1454ACNSR) and a 650V 5×6 mm PDFN package GaN E-HEMT, (GS-065-011-1-L).
The PWM control signal is generated internally by the PWM controller, U2.
The EZDrive®uses a Si MOSFET controller to drive a GaN HEMT which has a lower
threshold voltage than a Si MOSFET. The EZDrive®circuit is shown in the dotted box in
Figure 2. It is a low-cost, low component-count circuit composed of two Zener diodes,
one capacitor, three resistors and one diode.
ZDEZ1, ZDEZ2 clamp the positive and negative gate drive voltages. CEZ holds a negative
voltage for GaN E-HEMT turn-off. REZ sets the minimum driving current required to
keep the GaN E-HEMT fully turned on. RGcontrols the turn-on speed and ROFF controls
the turn-off speed.
The two operation modes for EZDrive®are:
•Mode 1: Assuming the Vcc of the controller is 12V and the controller output is
ON, the driving voltage on the GaN E-HEMT is clamped to 6V by Zener diode
ZDEZ. The rest of the Vcc, 6V, is stored across the capacitor CEZ.
•Mode 2: The voltage stored in CEZ is applied to the gate in reverse, allowing the
GaN E-HEMT e to be turned off quickly.
This circuit converts the Si MOSFET PWM controller’s output voltage to the proper
voltage thresholds for driving GaN Systems’ E-HEMTs.
Cautionary Notes
A Boost converter’s output voltage is higher than the input voltage, VIN.When operating
at a high duty cycle and low load/no load operating conditions, the output voltage will
rise and has the potential of damaging the GaN device. To avoid an overvoltage on the
GaN device, two actions are recommended.
First, always apply a load at the output voltage, VOUT.
Secondly, pre-set the PWM signal before applying power to VIN. Figure 4 shows the block
diagram of PWM signal generation inside the TL1454ACNSR.

GS65011-EVBEZ
EZDrive®Open Loop Boost Evaluation Board
Technical Manual
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PWM output
Duty Cycle Control
Freq control input
RT=120pF;
RT=R3+RT2=25kΩ;
Fsw=200kHz
Vpk=1.8V
Vvalley=1.2V
000 ohm)
Figure 4 • GS65011-EVBEZ PWM signal adjustment diagram
The PWM signal is adjusted by tuning the controller’s peripheral resistors, R11 and R3. Use the
Table 1 to set the duty cycle with R11. Use Table 2 to set the switching frequency with R3.
Select the appropriate values according to your own specifications and requirements. For a
safe start up, 10% duty cycle and frequency 250kHz is recommended.
Table 1 • PWM Duty Cycle Setting up table
R11 (Ω)
IN1+ (V)
Duty Cycle
Case 1
1000
1.83
0 %
Case 2
850
1.74
10 %
Case 3
500
1.52
47 %
Case 4
0
1.15
100 %
Table 2• PWM Frequency Setting up table
f
SW_MIN
f
SW
f
SW_MAX
R3 (kΩ)
20
5
0
CT (pF)
120
120
120
f
SW
(kHz)
200
500
900

GS65011-EVBEZ
EZDrive®Open Loop Boost Evaluation Board
Technical Manual
_____________________________________________________________________________________________________________________
GSWPT-EVBEZ Rev. 210307 © 2021 GaN Systems Inc. www.gansystems.com 9
Please refer to the Evaluation Board/Kit Important Notice on page 17
Quick Start Guide
This chapter will guide the user through the evaluation board overview, hardware
operation, test setup and test results.
Evaluation Board Overview
The evaluation board contains:
• Connectors for both high voltage (0Vdc < VIN < 200Vdc) and low voltage (5Vdc < VCC < 12Vdc)
power supplies
• Connector for the output load
• User-friendly probe connector and vias for VGS, VDS measurement and other performance
verification
• The jumper for current sensing
The operating specifications of the evaluation board are as follows:
• The recommended input voltage operating range is 0 V < VIN < 200 V. (The maximum input
voltage is limited by the output voltage of the Boost converter, which is further subject to
operating mode, the duty cycle and the load value.)
• Frequency of operation of 200 kHz - 900 kHz.
• The maximum load current depends on die temperature and is further subject to switching
frequency and operating voltage. Forced air cooling or heat sinking can increase current rating.

GS65011-EVBEZ
EZDrive®Open Loop Boost Evaluation Board
Technical Manual
_____________________________________________________________________________________________________________________
GSWPT-EVBEZ Rev. 210307 © 2021 GaN Systems Inc. www.gansystems.com 10
Please refer to the Evaluation Board/Kit Important Notice on page 17
Evaluation Test Setup
Figure 5 shows the test setup for the GS65011-EVBEZ evaluation board. Make sure that
the specified safety precautions mentioned in “Safety Precautions” on page 2 are
followed.
VCC Input
(5VDC<VCC<12VDC)
VIN Input
(0VDC<VIN<200VDC)
VOUT Output
PWM FREQ ADJ
PWM DUTY ADJ
VGS MEAS
VDS MEAS
Figure 5 • GS65011-EVBEZ Test Setup

GS65011-EVBEZ
EZDrive®Open Loop Boost Evaluation Board
Technical Manual
_____________________________________________________________________________________________________________________
GSWPT-EVBEZ Rev. 210307 © 2021 GaN Systems Inc. www.gansystems.com 11
Please refer to the Evaluation Board/Kit Important Notice on page 17
Hardware Operation
The general guidelines for operating the evaluation board are listed in this section. Follow
the steps to configure the hardware properly.
1) Always connect a load (E-load) to Vout+ and Vout-.
2) Pre-set the PWM frequency and the duty cycle (by tuning R3 and R11), according to
the PWM signal look-up tables. Start with 10% duty cycle and frequency 250kHz.
3) Apply VCC (5VDC < VCC < 12VDC) to Vcc+ and Vcc-, use T_GS (MMCX JACK) or G/SS
(VIAS) for VGS monitoring
4) Check the VGS waveform and fine-tune the PWM frequency (by tuning R3) and duty
cycle (by tuning R11)
5) For taking an efficiency measurement, add a current meter and use Vin+ and Vin- for
VIN and use Vout+ and Vout- for VOUT measurement.
6) Apply VDC to Vin+ and Vin- and sweep the voltage from low (0V) to max. Monitor
the output voltage and device temperature. Make sure VOUT is lower than 400V, and
the GaN device temperature is lower than 150°C. Note: the maximum input voltage
is limited by the output voltage of the Boost converter, which is dependent on the
operating mode, the duty cycle and the load value.
7) After testing, turn off VIN first, then VCC across Vcc+ and Vcc- last.

GS65011-EVBEZ
EZDrive®Open Loop Boost Evaluation Board
Technical Manual
_____________________________________________________________________________________________________________________
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Please refer to the Evaluation Board/Kit Important Notice on page 17
Note: When measuring the high frequency content switch node, care must be taken to
avoid long ground leads. Measure the switch node by placing the oscilloscope probe tip
through the Drain via and Source via (designed for this purpose). See Figure 6 for proper
probe technique and Figure 5 for the location of VGS and VDS measure vias. Use a high
voltage passive/differential probe for the VDS measurement.
Figure 6 • Proper Oscilloscope Probe Measurement Technique
Note: A jumper is placed between the Vin+ signal and the inductor (beneath the input
capacitor C4) The jumper can be replaced by a loop of jumper wire to take the inductor
current measurement.
Figure 7 shows the jumper location. Figure 8 shows how to replace the jumper with a loop
of jumper wire to take the current measurement with a current probe. The jumper wire
loop and the current probe are not included in the Evaluation Kit.

GS65011-EVBEZ
EZDrive®Open Loop Boost Evaluation Board
Technical Manual
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Jumper
Figure 7 • Current Sensing Jumper Location
Figure 8 • Inductor Current Probe Insert Example

GS65011-EVBEZ
EZDrive®Open Loop Boost Evaluation Board
Technical Manual
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Evaluation Results
The evaluation results are shown in Figures 7 through 10.
Figure 7 • Test Results at half load
VGS
VDS
f
sw
=250kHz
-6V
6V
IL
400V
Duty cycle=21%
Test conditions: VIN=200V; VOUT=400V; IOUT=0.25A; POUT=100W (half load); fSW=250kHz
Figure 8• Test Results at full load
VGS
VDS
-6V
6V
IL
fsw=250kHz
Duty cycle=49%
400V
Test conditions: VIN=200V; VOUT=400V; IOUT=0.5A; POUT=200W (full load); fSW=250kHz
POUT
Half load
(100W)
VIN 200V
VOUT 400V
Duty cycle 21%
fSW 250kHz
Efficiency 96%
POUT
Full load
(200W)
VIN 200V
VOUT 400V
Duty cycle 49%
fSW 250kHz
Efficiency 97.3%

GS65011-EVBEZ
EZDrive®Open Loop Boost Evaluation Board
Technical Manual
_____________________________________________________________________________________________________________________
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Figure 9 • Efficiency & GaN E-HEMT temperature vs load
Test conditions: VIN=200V, VOUT=400V, fSW=250kHz
Figure 10 • Efficiency & VIN vs load
Test conditions: Duty cycle=40.8%, VOUT =400V, fSW=250kHz
96%
96.70%
97.25% 97.27%
28.4
34.8
39.8
44.8
25
35
45
55
65
75
85
95
90%
91%
92%
93%
94%
95%
96%
97%
98%
30 50 70 90 110 130 150 170 190 210
Temperature (°C)
Efficiency (%)
P
out
(W)
Efficiency & GaN E-HEMTtemperature vs load
96.1% 95.8% 96.0%
97.0%
97.7%
193
196 197 197.3 198.08
202.4
209.2
180
185
190
195
200
205
210
215
90%
91%
92%
93%
94%
95%
96%
97%
98%
99%
100 110 120 130 140 150 160 170 180 190 200 210
VIN (V)
Efficiency (%)
Pout (W)
Efficiency & VIN vs load

GS65011-EVBEZ
EZDrive®Open Loop Boost Evaluation Board
Technical Manual
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Please refer to the Evaluation Board/Kit Important Notice on page 17
Thermal Considerations
The EVB includes one GS-065-011-1-L GaN E-HEMT. Although the electrical performance
surpasses that for traditional silicon devices, their relatively smaller size does magnify the
thermal management requirements. The evaluation board is intended for bench evaluation
under low ambient temperature and with convection cooling. The addition of heat-sinking
and forced air cooling can significantly increase the current rating of these devices, but care
must be taken to not exceed the absolute maximum junction temperature of +150 °C.
Note: The EVB does not include any on-board current or thermal protection.
The thermal performance of the EVB is shown in Figure 10 and Figure 11. Infrared thermography
was performed under the following conditions, with a fan on at room-ambient temperature:
• VIN = 200V
• VOUT = 400V
• IOUT = 0.5A
• fSW = 250 KHz
Figure 11 • Thermal imaging with an external fan (TMAX = 44.8˚C)
Technical Resources
This document and additional technical resources are available for download from
www.gansystems.com.

GS65011-EVBEZ
EZDrive®Open Loop Boost Evaluation Board
Technical Manual
_____________________________________________________________________________________________________________________
GSWPT-EVBEZ Rev. 210307 © 2021 GaN Systems Inc. www.gansystems.com 17
Please refer to the Evaluation Board/Kit Important Notice on page 17
Evaluation Board/kit Important Notice
GaN Systems Inc. (GaN Systems) provides the enclosed product(s) under the following AS IS conditions:
This evaluation board/kit being sold or provided by GaN Systems is intended for use for ENGINEERING
DEVELOPMENT, DEMONSTRATION, and OR EVALUATION PURPOSES ONLY and is not considered by
GaN Systems to be a finished end-product fit for general consumer use. As such, the goods being sold or provided
are not intended to be complete in terms of required design-, marketing-, and/or manufacturing-related protective
considerations, including but not limited to product safety and environmental measures typically found in end
products that incorporate such semiconductor components or circuit boards. This evaluation board/kit does not fall
within the scope of the European Union directives regarding electromagnetic compatibility, restricted substances
(RoHS), recycling (WEEE), FCC, CE or UL, and therefore may not meet the technical requirements of these
directives, or other related regulations.
If this evaluation board/kit does not meet the specifications indicated in the Technical Manual, the board/kit may
be returned within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE
EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES,
EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR
FITNESS FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER
PARTY SHALL BE LIABLE TO THE OTHER FOR ANY IN
DIRECT, SPECIAL, INCIDENTAL, OR
CONSEQUENTIAL DAMAGES.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user
indemnifies GaN Systems from all claims arising from the handling or use of the goods. Due to the open
construction of the product, it is the user’s responsibility to take any and all appropriate precautions with regard
to electrostatic discharge.
No License is granted under any patent right or other intellectual property right of GaN Systems whatsoever. GaN
Systems assumes no liability for applications assistance, customer product design, software performance, or
infringement of patents or any other intellectual property rights of any kind.
GaN Systems currently services a variety of customers for products around the world, and therefore this
transaction is not exclusive.
Please read the Technical Manual and, specifically, the Warnings and Restrictions notice in the Technical
Manual prior to handling the product. Persons handling the product(s) must have electronics training and
observe good engineering practice standards.
This notice contains important safety information about temperatures and voltages. For further safety concerns,
please contact a GaN Systems’ application engineer.

GS65011-EVBEZ
EZDrive®Open Loop Boost Evaluation Board
Technical Manual
_____________________________________________________________________________________________________________________
GSWPT-EVBEZ Rev. 210307 © 2021 GaN Systems Inc. www.gansystems.com 18
Please refer to the Evaluation Board/Kit Important Notice on page 17
In Canada:
GaN Systems Inc.
1145 Innovation Drive Suite 101
Ottawa, Ontario, Canada K2K 3G8
T [phone]
In Europe:
GaN Systems Ltd., German Branch
Terminalstrasse Mitte 18,
85356 München, Germany
T [phone]
In the United States:
GaN Systems Corp.
2723 South State Street, Suite 150,
Ann Arbor, MI. USA 48104
T [phone]
www.gansystems.com
Important Notice – Unless expressly approved in writing by an authorized representative of GaN Systems, GaN Systems components are
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