Applications Information
HCPL-3140/HCPL-0314 on a
small PC board directly above the
IGBT) can eliminate the need for
negative IGBT gate drive in many
applications as shown in
Figure 19. Care should be taken
with such a PC board design to
avoid routing the IGBT collector
or emitter traces close to the
HCPL-3140/HCPL-0314 input as
this can result in unwanted
coupling of transient signals into
the input of HCPL-3140/
HCPL-0314 and degrade
Eliminating Negative IGBT Gate
Drive
performance. (If the IGBT
drain must be routed near the
HCPL-3140/HCPL-0314 input,
then the LED should be reverse
biased when in the off state, to
prevent the transient signals
coupled from the IGBT drain
from turning on the HCPL-3140/
HCPL-0314.)
To keep the IGBT firmly off,
the HCPL-3140/HCPL-0314 has a
very low maximum V
OL
specification of 1.0 V. Minimizing
Rg and the lead inductance from
the HCPL-3140/HCPL-0314 to
the IGBT gate and emitter
(possibly by mounting the
HCPL-3140/HCPL-0314
+5 V
1
2
3
4
8
V
= 15 V
CC
+ HVDC
270 Ω
0.1 µF
+
–
7
Rg
Q1
3-PHASE
AC
CONTROL
INPUT
6
5
74XXX
OPEN
COLLECTOR
Q2
- HVDC
Figure 19. Recommended LED drive and application circuit for HCPL-3140/HCPL-0314.
11
AVAGO [ AVAGO TECHNOLOGIES LIMITED ]
