HCPL-J314 Datasheet, PDF (12/17 Pages) Agilent(Hewlett-Packard) – 0.4 Amp Output Current IGBT Gate Drive Optocoupler

12
Applications Information
Eliminating Negative IGBT
Gate Drive
To keep the IGBT firmly off,
the HCPL-J314 has a very low
maximum V_OL specification of
1.0 V. Minimizing Rg and
the lead inductance from the
HCPL-J314 to the IGBT gate and
emitter (possibly by mounting the
HCPL-J314 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-J314 input as this can
result in unwanted coupling of
transient signals into the input of
HCPL-J314 and degrade
performance. (If the IGBT
drain must be routed near the
HCPL-J314 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-J314.)
+5 V
1
270 Ω
2
CONTROL
INPUT
3
74XXX
OPEN
4
COLLECTOR
HCPL-J314
8
0.1 µF
7
6
+ ^{VCC = 15 V}
–
Rg
Q1
5
Q2
Figure 19. Recommended LED Drive and Application Circuit for HCPL-J314.
+ HVDC
3-PHASE
AC
- HVDC