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IGBT.ppt
- 1. 1 IGBT: Insulated-Gate Bipolar Transistor •Combination BJT and MOSFET – High Input Impedance (MOSFET) – Low On-state Conduction Losses (BJT) • High Voltage and Current Ratings • Symbol
- 2. 2 Cross-Sectional View ofan IGBT Metal Silicon Dioxide Metal Emitter
- 3. 3 IGBT Equivalent Circuitfor VGE<VT + VCC IEPNP ICPNP IBPNP ICNPN IENPN IBNPN Leakage Current IRBE Both transistors are OFF
- 4. 4 IGBT Equivalent Circuitfor VGE>VT + VCC NPN Transistor becomes forward biased at the BE, drawing current from the Base of the PNP transistor. MOS transistor conducts, drawing current from the Base of the PNP transistor. PNP transistor turns ON, RMOD decreases due to carrier injection from the PNP Emitter.
- 5. 5 Channel is InducedWhen VGE>VT Induced Channel electrons RMOD PNP RBE NPN
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- 7. 7 IGBT Output Characteristics Followsan SCR characteristic
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- 9. 9 Example of IGBTRatings • Used in high voltage / current & high frequency switching power applications (Inverters, SMPS). • Example: IGBT 2500V / 2400A. • Max. Frequency: 20KHz. • Switching time: 5 to sec. • On state resistance: 2.3m. 9
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- 17. 17 Turn-on time (ton)composed of two different times: Delay time (tdn) and Rise time (tr). ton = tdn + tr. Delay time tdn : Time for the VCE to fall from VCE to 0.9VCE. i.e., IC - 0 to 0.1IC (10%). Rise time tr : Time when VCE falls from 0.9VCE to 0.1 VCE. VCE falls to 10% from 90%. IC reaches final value of IC from10%.
- 18. 18 Turn-off time comprisesof three intervals: •Delay Time, tdf •Initial Fall Time, tf1 •Final Fall Time, tf2 i.e. toff = tdf + tf1 + tf2 Delay time: Time during which gate voltage falls from VGE to threshold voltage VGET. As gate voltage falls to VGE during tdf, the collector current falls from IC to 0.9IC. First fall time tf1 : Time during which IC falls from 90% to 20% of its final value IC or VCE rises from VCES to 0.1VCE. Final fall time tf2:Time during which IC falls from 20% to 10% of IC or VCErises from 0.1VCE to final value VCE.
- 19. Design of GateDriver circuits • Power electronics applications employ power device switches. • Every switch needs a driver – the right driver makes a difference. • Gate drivers provide a wide range of typical output current options, from 0.1-A up to 10-A. • Robust gate drive protection features such as fast short- circuit protection, active Miller clamp, shoot-through protection, fault, shutdown, and over current protection 19
- 20. Gate driver ICs •Gate driver ICs serve as the interface between control signals (digital or analog controllers) and power switches (IGBTs, MOSFETs, SiC MOSFETs, and GaNHEMTs). • The integrated gate driver solutions reduce our design complexity, development time, bill of materials (BOM), and board space while improving reliability over discretely-implemented gate-drive solutions. • Gate driver ICs with a variety of configurations, voltage classes, isolation levels, protection features, and package options. 20
- 21. Gate driver ICSelection By • Configuration • Isolation • Application • Switch device 21
- 22. Configuration • High side •Low side • High and Low side • Half bridge • Full Bridge • Three phase • Driver boards • Gate driver support Ics • Synchronous buck 22
- 23. Isolation • Level shift •Isolated • Non isolated 23
- 24. Applications • PFC • switchmode power supplies (SMPS), • battery powered application • computing • motor control and drives • UPS • Lighting • solar micro inverter • Automotive applications- electric motors, power steering, HVAC compressors, engine cooling fans H-bridge and three-phase automotive gate driver IC's 24
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