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A SPICE MODEL FOR IGBTs - Intusoft

Figure 2. SPICE compatible IGBT 10 CGE325 PFFBVFBEGD1 VFB0 CGD1NR11D1 DLIMD2 DLIMDHVDRR21 ESDPOLY(1)MLVSWDLVDRRLV (72)GATEV(71)COLLECTRV(73)EMITTER7317271 Figure 1. Basic IGBT subcircuitIntroductionYou ve finally tested a version of your design that seemsto work well, but you would feel a lot better if you KNEWthe circuit would work well with all the devices that thevendor will supply in production. You found a MODEL ina library, but you are not sure what specifications from thedata book apply to that MODEL . The following paragraphswill try to clarify the relationship between data bookspecifications and a new insulated gate bipolar transistor (IGBT) subcircuit SPICE An IGBTAn IGBT is really just a power MOSFET with an addedjunction in series with the drain.

specifications and a new Insulated Gate Bipolar Transistor (IGBT) subcircuit SPICE model. Modeling An IGBT An IGBT is really just a power MOSFET with an added ... A SPICE MODEL FOR IGBTs A. F. Petrie, Independent Consultant, 7 W. Lillian Ave., Arlington Heights, IL 60004

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Transcription of A SPICE MODEL FOR IGBTs - Intusoft

1 Figure 2. SPICE compatible IGBT 10 CGE325 PFFBVFBEGD1 VFB0 CGD1NR11D1 DLIMD2 DLIMDHVDRR21 ESDPOLY(1)MLVSWDLVDRRLV (72)GATEV(71)COLLECTRV(73)EMITTER7317271 Figure 1. Basic IGBT subcircuitIntroductionYou ve finally tested a version of your design that seemsto work well, but you would feel a lot better if you KNEWthe circuit would work well with all the devices that thevendor will supply in production. You found a MODEL ina library, but you are not sure what specifications from thedata book apply to that MODEL . The following paragraphswill try to clarify the relationship between data bookspecifications and a new insulated gate bipolar transistor (IGBT) subcircuit SPICE An IGBTAn IGBT is really just a power MOSFET with an addedjunction in series with the drain.

2 This creates a parasitictransistor driven by the MOSFET and permits increasedcurrent flow in the same die area. The sacrifice is anadditional diode drop due to the extra junction and turn-offdelays while carriers are swept out of this 1 shows a simplified schematic of an IGBT. Notethat what is called the collector is really the emitter of theparasitic PNP. What we have is a MOSFET driving anemitter follower. Although this MODEL is capable ofproducing the basic function of an IGBT, refinements arerequired for more accurate modeling and to emulate thenon-linear capacitance and breakdown IGBT ModelFigure 2 shows the complete subcircuit.

3 Table 1 shows thecorresponding SPICE compatible subcircuit netlistfor an International Rectifier IRGBC40U device [2]. Thesubcircuit is generic in nature, meaning, that componentvalues in the subcircuit can be easily recalculated toemulate different IGBT devices. The MODEL accuratelysimulates, switching loses, nonlinear capacitance effects,on-voltage, forward/reverse breakdown, turn-on/turn-offdelay, rise time and fall tail, active output impedance,collector curves including mobility s discuss the subcircuit one component at a time:Q1 is a PNP transistor which functions as an emitter-follower to increase the current handling ability of theIGBT.

4 BF (Forward Beta) is determined by the step in theturn-off tail which indicates the portion of the currenthandled by the PNP. TF (Forward Transit Time) controlsA SPICE MODEL FOR IGBTsA. F. Petrie, Independent Consultant, 7 W. Lillian Ave., Arlington Heights, IL 60004 Charles Hymowitz, Intusoft , 222 West 6th St. Suite 1070, San Pedro, CA 90731, (310) 833-0710, FAX (310) 833-9658, is the most popular program for simulating the behavior of electronic circuits. The biggeststumbling block that engineers run into is turning vendor data sheet specifications into SPICE models thatemulate real devices and run without convergence problems.

5 This is especially true for power devices, likeIGBTs, where the cost of testing and possibly destroying devices is prohibitive. The following paperdescribes the FIRST known SPICE subcircuit macro MODEL for IGBTs [1].tance curve. This diode includes breakdown voltage andcapacitor CBD as CJO. DBE, the B-E diode of the outputtransistor, emulates the reverse breakdown of the PNPbase-emitter junction (and of the IGBT). IS is made smalland N large to avoid shunting the junction in the , the collector resistance, represents the resistive part ofVCE(on). With the B-E diode, RC controls the VCE(on)voltage. RE, the emitter ohmic resistance, provides thefeedback between emitter current and gate voltage.

6 RG,the gate resistance, combines with the gate capacities inthe subcircuit to help emulate the turn-on and turn-offdelays, and the rise and fall , the gate -to-Emitter capacitor, equals Cies minusCres. CGC, the gate -to-Collector capacitor, is a fixedcapacitor representing package capacitances which areimportant at high voltages where Cres is are nine parts that replace the CGDO capacitor tomore accurately MODEL the change in capacitance withgate and drain voltage [5]. EGD is a voltage generatorequal to M1 s gate -to-drain voltage which is used tosupply voltage to the feedback capacitance emulatingsubcircuit.

7 VFB is a voltage generator used to monitor thecurrent in the feedback capacitance emulation subcircuitfor FFB. FFB is a current controlled current source usedto inject the feedback current back into M1. EGD, VFB,and FFB provide the necessary power to drive the feed-back components in parallel without loading M1. Theyalso permit ground connections in the subcircuit, improv-ing convergence and accuracy. CGD is the fixed part ofthe gate -to-drain capacitor. R1 and D1 limit its operationto the region where the gate voltage exceeds the drainvoltage. DHV is a diode which emulates the gate -to-draincapacitor at high voltages.

8 R2 and D2 limit its operationto the region where the drain voltage exceeds the gatevoltage. DLV is a diode which emulates the gate -to-draincapacitance variation with drain voltages (variable part ofCres) below the transition voltage. The multiplier (=C1/C2 - 1) used is determined by the size of the capacitancestep needed. RLV shunts its current to ground at highervoltages. ESD is a voltage controlled voltage source thatsenses source-to-drain voltage and drives MLV. ThePOLY form is used so that the proper offset voltage can beinserted without an additional element. MLV is used as aswitch to disconnect DLV from the feedback at highervoltages, emulating the drastic reduction in feedbackcapacitance with voltage found in most modern 1.

9 IRGBC40U IGBT IRGBC40U 71 72 74* TERMINALS: C G E* 600 Volt 40 Amp N-Channel IGBT 06-13-1992Q1 83 81 85 QOUTM1 81 82 83 83 MFIN L=1U W=1 UDSD 83 81 DODBE 85 81 DERC 85 71 83 73 72 82 82 83 82 71 1 PEGD 91 0 82 81 1 VFB 93 0 0 FFB 82 81 VFB 1 CGD 92 93 92 0 1D1 91 92 DLIMDHV 94 93 DRR2 91 94 1D2 94 0 DLIMDLV 94 95 DR 13 RLV 95 0 1 ESD 96 93 POLY(1) 83 81 19 1 MLV 95 96 93 93 SWLE 73 74 SW NMOS (LEVEL=3 VTO=0 KP=5). MODEL QOUT PNP (IS=377F NF= BF= CJE= + TF= XTB= ). MODEL MFIN NMOS (LEVEL=3 VMAX=400K THETA= ETA=2M+ VTO= KP= ). MODEL DR D (IS= CJO=100P VJ=1 M=.)

10 82). MODEL DO D (IS= BV=600 CJO= VJ=1 M=.7). MODEL DE D (IS= BV= N=2). MODEL DLIM D (IS=100N).ENDSthe turn-off tail time. The OFF control parameter can beadded to aid DC convergence by starting DC calculationswith Q1 turned M1 emulates the input MOSFET [3, 4]. TheBerkeley SPICE Level=3 MODEL is used in the .MODELMFIN statement in order to better MODEL modern devicecharacteristics. VMAX (Maximum Drift Velocity) con-trols the collector (drain) curves in the saturation region,and hence the VCE(on) voltage. THETA (Mobility Modu-lation Parameter) is used to reduce the gain at high gatevoltages which is normally exponential. ETA (StaticFeedback) is similar to the Early effect in bipolar tran-sistors and is used to control the slope of the collectorcurves in the active region and hence the output imped-ance.


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