HCPL3120000E AVAGO TECH, HCPL3120000E Datasheet - Page 18

• Manufacturer Part Number: HCPL3120000E
• Manufacturer: AVAGO TECH

CONTROL
Figure 26. HCPL-3120 Typical Application Circuit with Negative IGBT Gate Drive.
Selecting the Gate Resistor
(Rg) to Minimize IGBT
Switching Losses. (Discussion
applies to HCPL-3120, HCPL-
J312 and HCNW3120)
Step 1: Calculate Rg Minimum
from the I
tion. The IGBT and Rg in Figure
26 can be analyzed as a simple
RC circuit with a voltage supplied
by the HCPL-3120.
COLLECTOR
INPUT
+5 V
74XXX
OPEN
OL
270
Peak Specifica-
1
2
3
4
HCPL-3120
Rg
= –––––––––––––––
= ––––––––––––––––––
= 7.2
(V
–––––––––––––––
(V
(15 V + 5 V - 2 V)
8
7
6
5
0.1 µF
CC
CC
2.5 A
– V
I
– V
I
OLPEAK
OLPEAK
EE
EE
8
+
–
–
+
- V
- 2 V)
V
V
CC
EE
Rg
OL
= 15 V
= -5 V
)
Q1
Q2
18
The V
vious equation is a conservative
value of V
of 2.5A (see Figure 6). At lower
Rg values the voltage supplied by
the HCPL-3120 is not an ideal
voltage step. This results in lower
peak currents (more margin)
than predicted by this analysis.
When negative gate drive is not
used V
is equal to zero volts.
OL
EE
value of 2 V in the pre-
in the previous equation
OL
at the peak current
3-PHASE
+ HVDC
- HVDC
AC