1
Subject to change without notice.
www.cree.com
SiC MOSFET Isolated Gate Driver
SiC MOSFET Isolated Gate Driver
Bob Callanan, Cree Inc
CPWR-AN10, REV B
SiC MOSFET Isolated Gate Driver
This article describes an implementation of an isolated gate driver suitable for testing and
evaluating SiC MOSFETs in a variety of applications. This design replaces previous versions of
this application note and include new enhancements. The enhancements are as follows:
• Thecircuitboardhasbeenextendedsothatnow2wattaswellas1watt
DC-DC converters can be used. This enables driving larger MOSFETs or driving
of smaller MOSFETs at higher frequency.
• Thecreep/strikeclearancehasbeensignicantlyincreased.
• Aseparateregulatorhasbeenaddedfortheopto-isolator.Thisallowssimpler
bypassing of the DC-DC converters when non-isolated operation is desired.
• Theoutputresistornetworkhasbeenmodiedwithanadditionaldiodeto
allow separate optimization of turn-on and turn-off transitions.
The top and bottom view of the enhanced gate driver is shown in Figures 1 and 2. The
enhanced creep distance is accomplished with the groove in the printed circuit card. Some
ofthecomponentsarenotpopulatedbecauseoftheaddedexibilityinsettinguptheoutput
network.
The new schematic for the enhanced gate driver is shown in Figure 3. The circuit consists of
twoisolatedDC-DCconverters(X2andX3),anopto-isolator(U1)andthegatedriverinte-
gratedcircuit(U2).Thisintegratedcircuit,theClare/IXYSIXDN609SIcanprovide35Voutput
swingandup to9Aofcurrentwithatypicaloutputresistanceof0.8Ω.Theopto-isolator,
theAvagoACPL-4800-300E,hashighcommonmodetransientimmunity(30kV/µsec)andcan
operatefrom4.5to20V.Aprovisionforaninputlteringcapacitor(C4)hasbeenincluded
if needed. Power is provided by isolated DC-DC converters; one for the positive bias and the
otherfornegativebias.X2andX3arebothfromtheRecomRPseriesof1wattunregulated
isolatedDC-DCconvertersortheRecom[1]RxxP2xxseriesof2wattDC-DCconverters.Ei-
ther type can be accommodated depending on the application.
Figure 1: Isolated Gate Driver Top View Figure 2: Isolated Gate Driver Bottom View
2
CPWR-AN10, REV -B
SiC MOSFET Isolated Gate Driver
This document is provided for informational purposes only and is not a warranty or a specication.
For product specications, please see the data sheets available at www.cree.com/power. For warranty
information, please contact Cree Sales at PowerSales@cree.com.
Figure 3: Isolated Gate Driver Schematic
Theseconvertersareinexpensivewithanisolationvoltageratingof5.2kVandalsohaveverylow
isolationcapacitance.Inthisparticularconguration,X2isa12Vin5VoutconverterandX3is
a12Vin,+/-12Voutconverter.Asshownintheschematic,theoutputsoftheconvertersare
series connected and the common connection is referenced to the source terminal. Therefore, VCC
determines the gate pulse positive voltage and –VEE determines the negative gate pulse voltage. The
–VEE node is used as the ground reference for opto-isolator and the gate driver. The opto-isolator’s
maximumoperatingvoltageis20VwhichcanbegreaterthanthevoltageappearingatVCC.An
emitter follower clam consisting of Q1 and D1 has been added to limit the voltage to the opto-isolator
to17.3Vnominal.Abaseresistor(R16)wasincludedifadditionaldampeningisdesiredforthe
emitterfollower.Inpractice,azeroohmresistorworksne.ResistorsR2,R4,R5,R9-R15anddiode
D2canbepopulatedtoprovideoptimumturn-onandturn-offperformance.Inthiscase,onlyR2,R4
andR5arepopulatedwith20ohm1/3wattresistors.Tominimizestrayinductance,capacitorsC8-
C10 are located very close to the source output pin and the gate driver to provide very tight coupling
between the source output terminal and the –VEE node.
THESE COMPONENTS ARE LOCATED ON THE -VEE PLANE
0.100" ISOLATION
BOUNDRY SLIT
BOARD IF REQ.
VCC HIGH
INPUT HIGH
VCC HIGH RTN
INPUT LOW
VCC LOW
VC C LOW R TN
U2
IXDN609SI
VCC
1
IN
2
NC
3
GND
4
VCC 8
OUT 7
OUT 6
GND 5
R4 20 1210
J2
HEADER 6
1
2
3
4
5
6
R5 20 1210
C2
1U
0603
C7
4.7U
1206
U1
ACPL-4800-300E
NC
1
ANODE
2
C ATH
3
NC
4
VCC 8
NC 7
VO 6
GND 5
C10
10U 1210
R6 620
0805
C3
1U
0603
C6
100N
0805
R3 620
0805
R7
47K
0603
C4
TBD
0805
R14
20
R10 20 1210
C8
10N 1210
R8
47K
0603
X2
RP-1205S
+VI N
1
-VIN
2-VOUT 5
+VOUT 7
Q1
DXT2222A
R12
20
D2
DIODE
R1
10K
0805
JP1
HEADER 3
7
8
9
C5
100N
0805
X3
RP-1212D
+VI N
1
-VIN
2-VOUT 5
COM 6
+VOUT 7
R2 20 1210
R15
20
JP2
HEADER 3
10
11
12
C9
100N
R9 20 1210
C1
1U
0603
R11 20 1210
D1
MMSZ5248B-7-F
R13
20
VCC LOW
INPUT LOW
INPUT HIGH
VCC LOW RTN
VCC HIGH
SOURCE
GATE
+VC C
VCC HIGH RTN
-VEE
-VEE
-VEE
-VEE
-VEE
-VEE
SOURCE
-VEE
+VC C
SOURCE -VEE
+VC C
-VEE
-VEE
R16 0
0805
Operationofthegatedriverisasfollows.A+10to+12Vpulseisappliedtotheoptocausesthe
gateterminaltogohigh.Theintentofthiscircuitistoaffordthemaximumexibility.Therefore,
unregulated DC-DC converters were used so that the output gate pulse positive and negative voltage
levels can be adjusted at ground level. The gate voltage positive level is adjusted by varying the
voltage between the VCC HIGH and VCC HIGH RTN and the negative pulse level is adjusted by varying
the voltage between the VCC LOW and VCC LOW RTN pins. The procedure is to observe the output
of the gate driver board with an oscilloscope and adjust VCC HIGH and VCC LOW input voltages until
thegatepulseissettothedesiredvalues.Caremustbetakenduringadjustmenttoinsurethatthe
voltagebetweentheVCCand–VEEnodesdoesnotexceedthemaximumratingsofU2,whichis35V.
3
CPWR-AN10, REV -B
SiC MOSFET Isolated Gate Driver
This document is provided for informational purposes only and is not a warranty or a specication.
For product specications, please see the data sheets available at www.cree.com/power. For warranty
information, please contact Cree Sales at PowerSales@cree.com.
Figure 4: Non-Isolated Conguration Schematic
R9
ThecircuitcanbemodiedtoremovetheisolatedDC-DCconverterstoallowdirectconnectionof
VCC,source,and–VEEdirectlytoexternalpowersupplies.Thisisaccomplishedbyremovingthe
converters and replacing them with jumper wires. The schematic of this change is shown in Figure 4.
NoticethatX2andX3havebeenremovedandreplacedbyjumpersshownasthedarkbluenets.Also
note,thegatedrivercanalsobeconguredfornonegativegatebiasbynotpopulatingthenegative
gatebiasDC/DCconverterasshowninFigure5.NoticethatDC-DCconverterX3isnotpopulatedand
ajumperisplacedasshowninthedarkbluenet.
Non-regulated DC-DC converters are used in this design to allow convenient adjustment of the high
and low gate pulse amplitudes at ground level. The VCC high input sets the high level and the VCC
low input sets the low level. The procedure is to observe the output of the gate driver board with an
oscilloscope and adjust VCC high and VCC low until the output pulse high and low levels are set to the
desired values.
NC
THESE COMPONENTS ARE LOCATED ON THE -VEE PLANE
0.100" ISOLATION
BOUNDRY SLIT
BOARD IF REQ.
VCC HIGH
VCC HIGH RTN
INPUT HIGH
INPUT LOW
VCC LOW
VC C LO W R TN
U2
IXDN609SI
VCC
1
IN
2
NC
3
GND
4
VCC 8
OUT 7
OUT 6
GND 5
R4 20 1210
J2
HEADER 6
1
2
3
4
5
6
R5 20 1210
C2
1U
0603
C7
4.7U
1206
U1
ACPL-4800-300E
NC
1
ANODE
2
C ATH
3
NC
4
VCC 8
NC 7
VO 6
GND 5
C10
10U 1210
R6 620
0805
C3
1U
0603
C6
100N
0805
R3 620
0805
R7
47K
0603
C4
TBD
0805
R14
20
R10 20 1210
C8
10N 1210
R8
47K
0603
Q1
DXT2222A
R12
20
D2
DIODE
R1
10K
0805
JP1
HEADER 3
7
8
9
C5
100N
0805
R2 20 1210
R15
20
JP2
HEADER 3
10
11
12
C9
100N
R9 20 1210
C1
1U
0603
R11 20 1210
D1
MMSZ5248B-7-F
VCC LOW
R13
20
INPUT LOW
INPUT HIGH
VCC LOW RTN
SOURCE
GATE
+VC C
VCC HIGH RTN
VCC HIGH
-VEE
-VEE
-VEE
-VEE
-VEE
-VEE
SOURCE
-VEE
+VC C
SOURCE -VEE
+VC C
-VEE
-VEE
R16 0
0805
4
CPWR-AN10, REV -B
SiC MOSFET Isolated Gate Driver
This document is provided for informational purposes only and is not a warranty or a specication.
For product specications, please see the data sheets available at www.cree.com/power. For warranty
information, please contact Cree Sales at PowerSales@cree.com.
Figure 5: Isolated Conguration Schematic - No Negative Bias
THESE COMPONENTS ARE LOCATED ON THE -VEE PLANE
0.100" ISOLATION
BOUNDRY SLIT
BOARD IF REQ.
VCC HIGH
INPUT HIGH
VCC HIGH RTN
INPUT LOW
VCC LOW
VC C LO W RTN
U2
IXDN609SI
VCC
1
IN
2
NC
3
GND
4
VCC 8
OUT 7
OUT 6
GND 5
R4 20 1210
J2
HEADER 6
1
2
3
4
5
6
R5 20 1210
C2
1U
0603
C7
4.7U
1206
U1
ACPL-4800-300E
NC
1
ANODE
2
C ATH
3
NC
4
VCC 8
NC 7
VO 6
GND 5
C10
10U 1210
R6 620
0805
C3
1U
0603
C6
100N
0805
R3 620
0805
R7
47K
0603
C4
TBD
0805
R14
20
R10 20 1210
C8
10N 1210
R8
47K
0603
Q1
DXT2222A
R12
20
D2
DIODE
R1
10K
0805
JP1
HEADER 3
7
8
9
C5
100N
0805
X3
RP-1212D
+VI N
1
-VIN
2-VOUT 5
COM 6
+VOUT 7
R2 20 1210
R15
20
JP2
HEADER 3
10
11
12
C9
100N
R9 20 1210
C1
1U
0603
R11 20 1210
D1
MMSZ5248B-7-F
VCC LOW
R13
20
INPUT HIGH
VCC LOW RTN
GATE
INPUT LOW
VCC HIGH RTN
VCC HIGH
SOURCE
-VEE
+VC C
-VEE
-VEE
-VEE
-VEE
-VEE
-VEE
SOURCE
SOURCE
+VC C+VC C
-VEE
-VEE-VEE
R16 0
0805
The bill of materials for the isolated gate driver is shown in Table 1. Please note that different Recom
isolated DC-DC converters can be used. Also note that the photographs of the populated board shown
inFigures1and2areforreferenceonlyanddoesnotcorrelatetothisBOM.Also,C4,D2andR9-R15
are not populated so they are listed as TBD. It is up to the user to select these parts depending on the
application.
55
CPWR-AN10, REV -B
SiC MOSFET Isolated Gate Driver
Copyright © 2012 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree, the
Cree logo, and Zero Recovery are registered trademarks of Cree, Inc. Cree, Inc.
4600 Silicon Drive
Durham, NC 27703
USA Tel: +1.919.313.5300
Fax: +1.919.313.5451
www.cree.com/power
This document is provided for informational purposes only and is not a warranty or a specication. This product is currently
available for evaluation and testing purposes only, and is provided “as is” without warranty. For preliminary, non-binding product
specications, please see the preliminary data sheet available at www.cree.com/power.
Table 1: Isolated Gate Driver Bill of Materials
Item Quant. Ref. Des. Value Description Manufacturer ManufacturerP/N
1 3 C1,C2,C3 1U Capacitor,Ceramic1UF25VX5R
0603
AVX 06033D105MAT2A
21 C4 TBD Capacitor,CeramicTBD0805
32 C5,C6 100N Capacitor,Ceramic100n50V
X7R0805
Kemet C0805C104K5RACTU
4 1 C7 4.7U Capacitor,Ceramic4.7UF50V
X5R1206
Kemet C1206C475K5PACTU
51C8 10N Capacitor,Ceramic10n50VNP0
1210
Kemet C1210C103J5GACTU
61C9 100N Capacitor,Ceramic100n50V
X7R1206
Kemet C1206C104K5RACTU
7 1 C10 10U Capacitor,Ceramic10UF16V
X5R1210
Kemet C1210C106K4PACTU
81 D1 MMSZ5248B-
7-F
DIODEZENER18V500MWSOD-
123
Diodes Inc. MMSZ5248B-7-F
91D2 DIODE Diode,TBDSOD-123AC
10 2 JP1,JP2 HEADER 3 3 Pins Cut to length Sullins
Connector
Solutions
PBC36SAAN
11 1 J2 HEADER6 6PinsCuttolength Sullins
Connector
Solutions
PBC36SAAN
12 1 Q1 DXT2222A Transistor, NPN General Purpose,
40VSOT-23
Diodes Inc. DXT2222A-13
13 1 R1 10K Resistor,10k1/8W5%0805 Vishay/Dale CRCW080510K0JNEA
14 3 R2,R4,R5 20 Resistor,20Ohm1/3W5%
1210
Vishay/Dale CRCW121020R0JNEA
15 7R9-R15 TBD Resistor,TBD1/3W5%1210
16 2 R3,R6 620 Resistor,620Ohm1/8W5%
0805
Vishay/Dale CRCW0805620RJNEA
17 2 R7,R8 47K Resistor,47k1/10W5%0603 Vishay/Dale CRCW060347K0JNEA
18 1R16 0Resistor,10k1/8W5%0805 Vishay/Dale CRCW08050000Z0EA
19 1U1 ACPL-4800-
300E
Opto-Isolator Avago ACPL-4800-300E
20 1U2 IXDN609SI Gate Driver Non-Inverting IXYS IXDN609SI
21 1X2 RP-1205S DC/DCConverter,1W12Vin Recom RP-1205S
5Vout
22 1 X3 RP-1212D DC/DCConverter,1W12Vin Recom RP-1212D
+/-12Vout
23 1 - - ISOLATEDGATEDRIVERREV5
PCB
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