ACPL-38JT View Datasheet(PDF) - Avago Technologies
Part Name
Description
MFG CO.
'ACPL-38JT' PDF : 33 Pages View PDF
1 GND1
2 VIN+
VE 16
VLED2+ 15
100pF
3 VIN
DESAT 14
4 VCC1
5 RESET
VCC2 13
VEE 12
RC8Ω
6 FAULT
VC 11
10Ω
7 VLED+
VOUT 10 10nF
8 VLED
VEE 9
15V
-5V
VE 16
VLED2+ 15
DESAT 14
VCC2 13
VEE 12
VC 11
VOUT 10
VEE 9
100pF
10Ω
10nF
15V
MJD44H11 or
D44VH10
4.5Ω
2.5Ω
MJD45H11 or
D45VH10
-5V
Figure 73. Use of RC to further limit ION,PEAK.
Figure 74. Current buffer for increased drive current
Higher Output Current Using an External Current Buffer:
To increase the IGBT gate drive current, a non-inverting
current buffer (such as the npn/pnp buffer shown in Figure
74) may be used. Inverting types are not compatible with
the de-saturation fault protection circuitry and should be
avoided. To preserve the slow IGBT turn-off feature during
a fault condition, a 10 nF capacitor should be connected
from the buffer input to VEE and a 10 W resistor inserted
between the output and the common npn/pnp base. The
MJD44H11/MJD45H11 pair is appropriate for currents up
to 8A maximum. The D44VH10/ D45VH10 pair is appropri-
ate for currents up to 15 A maximum.
DESAT Diode and DESAT Threshold
The DESAT diode’s function is to conduct forward current,
allowing sensing of the IGBT’s saturated collector-to-
emitter voltage, VCESAT, (when the IGBT is “on”) and to
block high voltages (when the IGBT is “off”). During the
short period of time when the IGBT is switching, there is
commonly a very high dVCE/dt voltage ramp rate across
the IGBT’s collector-to-emitter. This results in ICHARGE (=
CD-DESAT x dVCE/dt) charging current which will charge
the blanking capacitor, CBLANK. In order to minimize this
charging current and avoid false DESAT triggering, it
is best to use fast response diodes. Listed in the below
table are fast-recovery diodes that are suitable for use as
a DESAT diode (DDESAT). In the recommended application
circuit shown in Figure 61, the voltage on pin 14 (DESAT)
is VDESAT = VF + VCE, (where VF is the forward ON voltage
of DDESAT and VCE is the IGBT collector-to-emitter voltage).
The value of VCE which triggers DESAT to signal a FAULT
condition, is nominally 7V – VF. If desired, this DESAT
threshold voltage can be decreased by using multiple
DESAT diodes in series. If n is the number of DESAT diodes
then the nominal threshold value becomes VCE,FAULT(TH) =
7 V – n x VF. In the case of using two diodes instead of one,
diodes with half of the total required maximum reverse-
voltage rating may be chosen.
Part Number
MUR1100E
MURS160T3G
UF4007
BYV26E
Manufacturers
ON Semiconductor
ON Semiconductor
Vishay General Semi.
Vishay General Semi.
trr (ns)
75
75
75
75
Max. Reverse Voltage Rating
VRRM (Volts)
Package Type
1000
59-04 (axial leaded)
600
Case 403A (surface mount)
1000
DO-204AL (axial leaded)
1000
SOD57 (axial leaded)
29
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