Gan Systems GS65011-EVBEZ Manuale d'uso - Pagina 8

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A Boost converter's output voltage is higher than the input voltage, V
cycle and low load/no load operating conditions, the output voltage will rise and
potentially damage 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.
Duty Cycle Control
Figure 4 •
The PWM signal is adjusted by tuning the controller's peripheral resistors, R11 and R3. Use the
to set the duty cycle with R11. Use
Table 1
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
Table 2 •
PWM Frequency Setting up table
GSWPT-EVBEZ Rev190621
EZDrive
000 ohm)
Freq control input
RT=120pF;
RT=R3+RT2=25kΩ;
Fsw=200kHz
GS65011-EVBEZ PWM signal adjustment diagram
Table 2
R11 (Ω)
Case 1
1000
Case 2
850
Case 3
500
Case 4
0
f
SW_MIN
R3 (kΩ)
20
CT (pF)
120
f
(kHz)
200
SW
© 2019 GaN Systems Inc.
Please refer to the Evaluation Board/Kit Important Notice on page 15
Open Loop Boost Evaluation Board
TM
Under high duty
IN.
.
Figure 4
IN
PWM output
Vpk=1.8V
Vvalley=1.2V
to set the switching frequency with R3.
IN1+ (V)
Duty Cycle
1.83
0 %
1.74
10 %
1.52
47 %
1.15
100 %
f
f
SW
SW_MAX
5
0
120
120
500
900
www.gansystems.com
GS65011-EVBEZ
User's Guide
.
OUT
shows the block
8