HCPL-314J_11 Datasheet, PDF (10/14 Pages) AVAGO TECHNOLOGIES LIMITED – 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 applica-
tions as shown in Figure 19. Care should be taken with
such a PC board design to avoid routing the IGBT collec-
tor or emitter traces close to the HCPL-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 protec-
tion of HCPL-314J in the case of IGBTs switching induc-
tive 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
10