Gan Systems GS-EVB-HB-0650603B-HD, Техническое руководство

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GS-EVB-HB-0650603B-HD
Half Bridge Bipolar Drive Switch Board
Technical Manual
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GS-EVB-HB-0650603B-HD TM Rev. 210712 © 2021 GaN Systems Inc www.gansystems.com 8
Please refer to the Evaluation Board/Kit Important Notice on page # 16
𝑖
𝐶
𝐺𝐷
= 𝐶
𝐺𝐷
𝑑𝑉
𝐷𝑆_𝐿
𝑑𝑡
flowing in the gate-drain capacitance, C
GD,
and driver output. It will cause the voltage on the gate of the
low side FET to rise. If this voltage spike peaks beyond the threshold voltage V
TH,
the FET will conduct.
Considering that the high side FET is also conducting, this can result in a potentially destructive shoot-
through event.
The GS-EVB-HB-0650603B-HD EVB uses a bipolar gate drive arrangement which is useful to mitigate
against the effects of gate-drain capacitor currents. The secondary supply voltage V
SEC
is a function of the
primary supply voltage V
DRV
. The zener diode, CR1, will regulate the positive turn on voltage of the GaN
FET. During the turn-off of period, the gate voltage will be negative with a value of:
V
GS_OFF
= V
SEC
– V
ZENER
. V
SEC
is typically 9 V.
This negative V
GS_OFF
voltage allows more margin before the threshold voltage can be reached.
Figure 5: Bi-polar gate drive schematic
2.5 Propagation Delay
• V
DRV
= 12V
• Input = 100kHz
• R
PU
= 10R, R
PD
= 1R
• Power train un-loaded. That is, VHV+ = 0V.