Typical Fault Protected IGBT Gate Drive Circuit
The ACPL-516x is an easy-to-use, intelligent gate driver
age lockout (UVLO),“soft”IGBT turn-off and isolated fault
feedback provide maximum design flexibility and circuit
protection.
which makes IGBT V fault protection compact, afford-
CE
able, and easy-to-implement. Features such as user con-
figurable inputs, integrated V detection, under volt-
CE
ACPL-516x
1
2
3
4
5
6
7
8
V
V
V
V
16
15
IN+
IN-
E
C
BLANK
100 Ω
*
V
LED2+
D
DESAT
DESAT 14
CC1
+
–
+
–
µC
V
F
GND1
RESET
FAULT
V
13
12
11
10
9
CC2
R
F
+
–
+
–
+
–
V
C
R
G
*
V
V
CE
CE
V
OUT
V
V
+
–
*
LED1+
EE
V
V
EE
LED1-
R
PULL-DOWN
* THESE COMPONENTS ARE ONLY REQUIRED WHEN NEGATIVE GATE DRIVE IS IMPLEMENTED.
Figure 1. Typical desaturation protected gate drive circuit, noninverting
Description of Operation during Fault Condition
Output Control
1. DESATterminalmonitorstheIGBTV voltagethrough The outputs (V
and FAULT) of the ACPL-516x are con-
CE
OUT
D
.
trolled by the combination of V , UVLO and a detected
DESAT
IN
IGBT Desat condition. As indicated in the below table, the
ACPL-516x can be configured as inverting or non-invert-
2. When the voltage on the DESAT terminal exceeds 7V,
the IGBT gate voltage (V ) is slowly lowered.
OUT
ing using the V or V inputs respectively. When an in-
IN+
IN-
3. FAULT output goes low, notifying the microcontroller
of the fault condition.
verting configuration is desired, V must be held high
IN+
and V toggled. When a non-inverting configuration is
IN-
4. Microcontroller takes appropriate action.
desired, V must be held low and V
toggled. Once
IN-
IN+
UVLO is not active (V
- V > V
), V
UVLO
is allowed to
OUT
CC2
E
go high, and the DESAT (pin 14) detection feature of the
ACPL-516x will be the primary source of IGBT protection.
UVLO is needed to ensure DESAT is functional. Once V
U-
<
> 11.6 V, DESAT will remain functional until V
VLO+
UVLO-
12.4 V. Thus, the DESAT detection and UVLO features of
the ACPL-516x work in conjunction to ensure constant
IGBT protection.
Desat Condition
Detected on
Pin 14
X
Pin 6
UVLO
(FAULT)
Output
X
V
X
X
Low
X
V
X
X
X
High
Low
(V - V )
V
OUT
IN+
IN-
CC2
E
Active
Low
Low
Low
Low
High
X
X
X
Yes
X
X
Low
X
X
High
Not Active
No
High
2