GaN EZ Drive GS65011-EVBEZ Техническое руководство - Страница 7
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Circuit Description
The GS65011-EVBEZ EVB is a GaN-based open-loop DC/DC Boost converter. It is
assembled with the EZDrive
(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
Figure
2. It is a low-cost, low component-count circuit composed of two Zener diodes,
one capacitor, three resistors and one diode.
ZD
, ZD
clamp the positive and negative gate drive voltages. C
EZ1
EZ2
voltage for GaN E-HEMT turn-off. R
keep the GaN E-HEMT fully turned on. R
the turn-off speed.
The two operation modes for EZDrive
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
ZD
The rest of the Vcc, 6V, is stored across the capacitor C
EZ.
Mode 2: The voltage stored in C
•
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, V
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, V
Secondly, pre-set the PWM signal before applying power to V
diagram of PWM signal generation inside the TL1454ACNSR.
GSWPT-EVBEZ Rev. 210307
EZDrive
GaN driving circuit, a Si MOSFET PWM controller
®
sets the minimum driving current required to
EZ
controls the turn-on speed and R
G
are:
®
is applied to the gate in reverse, allowing the
EZ
© 2021 GaN Systems Inc.
Please refer to the Evaluation Board/Kit Important Notice on page 17
®
Open Loop Boost Evaluation Board
circuit is shown in the dotted box in
®
holds a negative
EZ
.
EZ
When operating
IN.
.
OUT
.
Figure 4
IN
www.gansystems.com
GS65011-EVBEZ
Technical Manual
controls
OFF
shows the block
7