HCPL-314J Datasheet, PDF (11/15 Pages) Agilent(Hewlett-Packard) – 0.4 Amp Output Current IGBT Gate Drive Optocoupler

Applications Information
Eliminating Negative IGBT Gate Drive
To keep the IGBT firmly off, the HCPL-314J has a very low
maximum V_OL specification of 1.0 V. Minimizing Rg and
the lead inductance from the HCPL-314J to the IGBT gate
and emitter (possibly by mounting the HCPL-314J 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 theHCPL-314J input as this can
result in unwanted coupling of transient signals into the
input of HCPL-314J and degrade performance. (If the IGBT
drain must be routed near the HCPL-314J 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-314J.) An external clamp diode
may be connected between pins 14 & 15 and pins 9 & 10
(as shown in Figure 19) for the protection of HCPL-314J
in the case of IGBTs switching inductive load.
+5 V
1
CONTROL
270 Ω
INPUT
2
74XX
OPEN
COLLECTOR
3
GND 1
+5 V
6
270 Ω
CONTROL
INPUT
7
74XX
OPEN
COLLECTOR
8
GND 1
HCPL-314J
16
0.1 µF
15
14
FLOATING
SUPPLY
V_CC = 18 V
+
–
Rg
V_OL
11
0.1 µF
10
9
V_CC = 18 V
+
–
Rg
Figure 19. Recommended LED Drive and Application Circuit for HCPL-314J.
+ HVDC
3-PHASE
AC
- HVDC
11