RC-Drives Cost-Optimized IGBT for Consumer Drive Application Reverse Conducting IGBT for Drives RC-Drives Cost-Optimized IGBT for Consumer Drive Application Application Note System Application IGBT November 2009, Davide Chiola Power Management Discretes 1 RC-Drives Cost-Optimized IGBT for Consumer Drive Application Edition Doc_IssueDate Published by Infineon Technologies AG 81726 Munich, Germany © 2010 Infineon Technologies AG All Rights Reserved. Legal Disclaimer The information given in this document shall in no event be regarded as a guarantee of conditions or characteristics. With respect to any examples or hints given herein, any typical values stated herein and/or any information regarding the application of the device, Infineon Technologies hereby disclaims any and all warranties and liabilities of any kind, including without limitation, warranties of non-infringement of intellectual property rights of any third party. Information For further information on technology, delivery terms and conditions and prices, please contact the nearest Infineon Technologies Office (www.infineon.com). Warnings Due to technical requirements, components may contain dangerous substances. For information on the types in question, please contact the nearest Infineon Technologies Office. Infineon Technologies components may be used in life-support devices or systems only with the express written approval of Infineon Technologies, if a failure of such components can reasonably be expected to cause the failure of that life-support device or system or to affect the safety or effectiveness of that device or system. Life support devices or systems are intended to be implanted in the human body or to support and/or maintain and sustain and/or protect human life. If they fail, it is reasonable to assume that the health of the user or other persons may be endangered. 2 RC-Drives Cost-Optimized IGBT for Consumer Drive Application Table of Contents 1. Short description of the product family……………………………………….…………..…....4 2. Technology overview…………………………………………….……………………………..….5 3. Chip Shrink and power density increase…...…………………………………...………..…….7 4. Static and dynamic behavior………………………………………....….…………………...….8 4.1. Static behavior…………………………………………………........…………………….…....8 4.2. Dynamic behavior…………………………………….…………….……………………..…....9 4.3. Short Circuit capability…………………………………….…………………........................11 5. EMI Consideration and Rg selection……………………………..…………………………….12 6. Power Losses in a BLDC Motor…………………………………………………………….…..14 7. Thermal behavior ………………………………………………………..……………………….16 7.1. Washing Machine application test………………………...………………………………….16 7.2. Mounting and cooling considerations…………………………………………………...…...19 7.2.1. Surface mounted package …………………………….………………………...…...19 7.2.2. Straight leads package………………………..…………………………………..…..21 3 RC-Drives Cost-Optimized IGBT for Consumer Drive Application 1. Short Description As a further evolution of the TRENCHSTOP™ in the price-sensitive Consumer Drive market, Infineon has released a new product family in the 600V voltage class. Purpose of this note is to illustrate the key features of the new technology, highlight the potential benefit for the customer as well as advantages over existing solutions, and to provide recommendations for the utilization in an inverter motor drive circuit. RC-Drives Product family Max Part Package number Type Inverter Heatsink Output needed IPAK IKD04N60 DPAK IKU06N60 IPAK IKD06N60 DPAK IKU10N60 IPAK IKD10N60 DPAK IKU15N60 IPAK IKD15N60 DPAK Ic@25C Ic@100C Power [W] IKU04N60 BVces Vce(on) Ets @ @ 175C 175C Ic@100C Typical Typical Tsc Vgeth [V] [A] [A] [V] [mJ] [usec] [V] 200 NO 600 8 4 1.85 0.40 5 5 600 YES 600 12 6 1.85 0.56 5 5 1000 YES 600 20 10 1.85 0.93 5 5 1500 YES 600 30 15 1.85 1.25 5 5 The product family can be used in a wide range of applications: Appliance Motor Drives Air Conditioning Compressors, Fan Washing machines Refrigerator Compressors 4 RC-Drives Cost-Optimized IGBT for Consumer Drive Application Vacuum cleaners Dishwashers Ventilation Fans General purpose Motor Drives Pumps 2. Technology Overview Infineon has pioneered over the last 20 years the Trench Field Stop IGBT Technology (TRENCHSTOPTM), combination of Field Stop concept in thin wafer technology and ´trench gate, with voltage classes spanning from 600V to 6500V. The RC-Drives technology is based on the established Trench Field Stop IGBT platform and tailored to the needs of the low-cost highvolume consumer market: the freewheeling diode is monolithically integrated in the IGBT chip, thus achieving substantial Si area saving: Figure 1: Reverse Conducting IGBT construction 5 RC-Drives Cost-Optimized IGBT for Consumer Drive Application The chip construction is similar to the previously released RC-H IGBT (Reverse Conducting for Induction Heating), however the integrated diode had to be improved in order to sustain hard switching conditions typical of inductive load in motor drive applications. This is realized by engineering the carrier profile inside the chip: Reduction of anode efficiency to reduce Qrr, Irr Lifetime killing process to speed-up depletion of the base from free-carrier Increase of cathode n-emitter efficiency to increase diode softness. Thanks to these modifications, Qrr and Irr during reverse recovery are reduced, insuring reduced power dissipation at IGBT turn-on in half bridge hard-switching voltage source inverters typical of motor drives. Beside Si area saving, additional advantages of the RC-Drives technology are: Reduction of wafer testing costs Reduction of assembly costs (single pass in chip bonding) More degrees of freedom in package layout Small „diodes“ can still be bonded with „thick“ bond wires Low thermal resistance of the diodes thanks to wider conduction area 6 RC-Drives Cost-Optimized IGBT for Consumer Drive Application 3. Chip shrink and power density increase Thanks to the reduced total chip size, packages of reduced footprint can be used for the same current rating of equivalent DuoPAK Products, thus allowing a substantial power density increase: Conventional Footprint Height RC- Footprint Height Footprint Height technology [mm2] [mm] Drives [mm2] [mm] reduction reduction TO-220 157 4.5 IPAK 39 2.3 -75% -49% D²PAK 106 4.5 DPAK 39 2.3 -63% -49% Note: To keep the Tj below 175°C, additional cooling effort may be needed. As a reference, refer to options provided in Chapter 7. Smaller package means less board spacing and compact system design. Although board spacing is normally not an issue in House Appliances, newer generation of Products could take advantage of a reduced board real estate for the power section: for example washing machines with increased drum size that must maintain the external outline, Industrial fan of Refrigerator compressors were the inverter board is mounted directly close to the motor. DPAK 3phase Figure 2: example of board space saving from RC-Drive in DPAK and IPAK package comparison 7 RC-Drives Cost-Optimized IGBT for Consumer Drive Application 4. Static and Dynamic Behaviour 4.1 Static Behaviour The RC-Drives IGBT is optimized for low Vcesat, because the conduction losses are dominant in the switching frequency range typical of motor drive application (4~16 kHz). Low Vcesat allows: Reduced losses and improve system efficiency Reduced number of devices in parallel for high power systems Reduced heatsink size 8 RC-Drives Cost-Optimized IGBT for Consumer Drive Application Figure 3: Output characteristics of RC-Drives IGBT. 9 RC-Drives Cost-Optimized IGBT for Consumer Drive Application 4.2 Dynamic Behaviour Due to the optimization for low Vcesat, the RC-Drives tends to show long tail currents at turn-off (Figure 4). Figure 4: Turn-off Transient Waveforms The turn-off losses at same dV/dt are higher compared to the DuoPAK (IKP06N60T) and to Competitor 1. These devices show however some non linear dI/dt characteristics that would generate harmonics of the radiated EMI noise (see next chapter). Competitor 2 shows similar turn-off current waveform resulting in similar turn-off losses as the RC-Drives. A trade-off chart Vcesat - Eoff is summarized in Fig. 5. 10 RC-Drives Cost-Optimized IGBT for Consumer Drive Application Trade Off IGBT @ T=175°C @dVcesat/dt=7kV/µs 400 RCDrive -Ipak 350 TO220 Eoff [µJ] 300 250 IGU06N60R TrenchStop - TO220 200 IKP06N60T 150 Competitor 2 TO220 100 Competitor 1 50 0 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 Vce(sat) [V] Figure 5: Trade-off Vcesat - Eoff 4.3 Short Circuit Capability The monolithic integration of the antiparallel diode does not degrade the short circuit capability in comparison with the TRENCHSTOPTM. The RC-Drives is rated at tsc=5usec at Tj=150°C, Vge=15V, Vcc=400V. The destruction mechanism is thermal run-away after successful turn-off (Figure 6), confirming the robust latch-up free Trench cell design. The failure mechanism of thermal destruction was validated by electro-thermal simulation: for long enough SC pulses, the device cannot dissipate the energy of the pulse, the Junction temperature increases and the Ices leakage is running away. 11 RC-Drives Cost-Optimized IGBT for Consumer Drive Application V, I R. Weiss MP#4 Zeljko-Ansteuerung 5 4 Ug ref Uce ref Ic ref Ug dut Uce dut Ic dut Vge 3 2 Vce 1 0 -1 -2 Ic -3 -4 -5 0 1 2 3 4 5 IGU06N60R_#C Vce 100V/div, NP -4 Ic 5A/div, NP -4 Vgs 5V/div, NP 0 Vce [V]: 400 Rg [Ohm]: 23 Ice [A]: NaN Vge [V]: 15 6 7 8 9 10 t [µs] IGU06N60R tdoff [ns]: 0 tf [ns]: 0 tf Tang. [ns]: 0 dUce/dt [V/ns]: 0 dIc/dt [A/µs]: 0 Vce 100V/div, NP -4 tdoff [ns]: 0 Ic 5A/div, NP -4 tf [ns]: 0 tf Tang. [ns]: 0 dUce/dt [V/ns]: 0 dIc/dt [A/µs]: 0 Eoff [mJ]: 0 Vgs 5V/div, NP 0 Vce [V]: 400 Eoff [mJ]: 0 Ice [A]: NaN Rg [Ohm]: 23 Vge [V]: 15 T [°C]: 150 T [°C]: 150 Figure 6: Typical short circuit waveform of a failing device. Thermal failure is happening well after turn-off. Vge=15V, Vce=400V, Tj=150°C. 5. EMI consideration and Rg section EMI is mainly driven by rate of change of voltage and current during switching events. Switching behavior as a function of Rg and Tj was investigated to assess the EMI performance in a real inverter circuit. Results for the RC-Drives are compared with the previous generation TRENCHSTOPTM and other competitors. Specifically the dV/dt behavior is plotted in Figure 7. 12 RC-Drives Cost-Optimized IGBT for Consumer Drive Application Turn-off dU/dt Turn-on dU/dt Vce=400V Ic=6A Rg=24Ohm Vce=400V Ic=6A Rg=24Ohm 0 20 18 IGU06N60R IKP06N60T Competitor1 Competitor2 -5 IGU06N60R IKP06N60T Competitor1 Competitor2 dUceoff/dt [V/µs] dUceoff/dt [V/µs] 16 14 12 10 RCDrive RCDrive -10 -15 -20 8 -25 6 4 0 50 100 150 200 -30 0 50 T [°C] Turn-off dU/dt Vce=400V Ic=6A T=175°C Turn-on dU/dt 14 150 200 Vce=400V Ic=6A T=175°C 0 12 IGU06N60R IKP06N60T Competitor1 Competitor2 -5 10 Uceon/dt [V/ns] dUceoff/dt [V/µs] 100 T [°C] 8 6 4 -10 -15 -20 2 IGU06N60R IKP06N60T Competitor1 Competitor2 -25 0 0 50 100 150 200 0 50 100 150 200 Rg [Ohm] Rg [Ohm] Figure 7: dV/dt as a function of Tj and Rg. The RC-Drives show the lowest dV/dt over the entire temperature range that will translate in lower high frequency harmonics of radiated EMI noise. The Rg can be reduced in order to reduce switching losses still maintaining low EMI. 13 RC-Drives Cost-Optimized IGBT for Consumer Drive Application 6. Power Losses in a BLDC Motor On the basis of the measured conduction and switching losses, the power losses of a real 3phase voltage source Inverter driving a BLDC motor were estimated. The modulation type is hard switching (Fig 8), were both conduction and switching losses are playing a significant role: Hard Switching Modulation Figure 8: Hard switching of a 3-phase voltage source inverter Vcc=400V, Rg =24 Ohm, Iout=6A. hard switching Simulations results for the 6A RC-Drives in IPAK are shown in Fig 9. At 4 kHz the conduction losses are dominating the overall losses, and the RC-Drives show low power dissipation aligned with competitors devices in TO-220 package. At 16 kHz the switching losses are taking over, 14 RC-Drives Cost-Optimized IGBT for Consumer Drive Application and the RC-Drives is penalized. Rg is set to 24 Ohm for all devices, a reduction of Rg for the RCDrives would have reduced the power dissipation in this case. The TRENCHSTOPTM in TO-220 P package shows the lowest losses for fsw<15 kHz. B6-Inverter Hardswitching Tj = 25°C 3.5 IKU06N60R 3.3 Ptot [W] IFX RCD IPAK IKP06N60T IRGB4045 Comp.1 3.0 2.8 IFX Duopak TO220 Comp.2 STGP10NC60 2.5 2.3 2.0 1.8 1.5 0 2 4 6 8 10 12 14 16 18 20 18 20 f [kHz] B6-Inverter Hardswitching Tj = 175°C 3.5 IKU06N60R 3.3 IKP06N60T Ptot [W] 3.0 IRGB4045 Comp.1 2.8 Comp.2 STGP10NC60 2.5 2.3 2.0 1.8 1.5 0 2 4 6 8 10 f [kHz] 15 12 14 16 RC-Drives Cost-Optimized IGBT for Consumer Drive Application BLDC Motor, Hard Switching modulation 400V, Ic=6A, DC=0.65, Tj=175C BLDC Motor, Hard Switching modulation 400V, Ic=6A, DC=0.65, Tj=175C fsw=4kHz 4.0 Diode sw. 3.5 Diode cond IGBT sw IGBT cond 2.5 2.0 1.5 1.0 3.0 Power losses (W) Power Losses (W) Diode sw. 3.5 IGBT sw 3.0 fsw=16kHz 4.0 Diode cond IGBT cond 2.5 2.0 1.5 1.0 0.5 0.5 0.0 0.0 IKU06N60R IRGB4045 Comp.1 STGP10NC60 Comp.2 IKP06N60T IKU06N60R IRGB4045 Comp.1 STGP10NC60 Comp.2 IKP06N60T Figure 9: Power loss vs. switching frequency and loss breakdown for individual switch 7. Thermal Behaviour 7.1 Washing Machine Application Test. In order to verify the thermal behavior of the RC-Drives, an application test was performed in a commercial AEG Washing machine. The original Electrolux board was equipped with TO-220 FullPAK device from competition. The HS and LS TO-220 FullPAK for one phase were replaced with RC-Drives in IPAK (Fig 10). Thermal foil was added to insulate the package from the heatsink. 16 RC-Drives Cost-Optimized IGBT for Consumer Drive Application Figure 10: Application test set-up For the case temperatures of the high side and low side IGBTs a thermocouple is inserted on a small hole drilled in the molding compound on the side of the package. The resulting temperature readings are very close to the junction temperature. For the heatsink temperature a small hole is also drilled in the heatsink in the vicinity of the low side device, and a third thermocouple is inserted. Temperatures are recorded during a “20 min” Washing-RinsingSpinning cycle with approx 5 Kg of load, 1200 rpm and 30°C water temperature (Fig11). The difference between junction and ambient temperature Tj and Ta is directly related to the power losses and thermal resistance: Tj -Ta = (Rthjc + Rthcs ) x Ptot + Rthsa x Ptot x 6 Were Ptot= Average Power loss IGBT + Diode for one device. The result (Fig. 12) shows only 15 °C maximum increase in Tj of the RC-Drives in IPAK in comparison with the commercial solution in TO-220 FullPAK from competition, and 90°C of Tjmax. In a worst case of a max Ta in a real application of approx 70°C, the resulting Tjmax would be approx. 135°C, well within the Tjmax specification of 175°C. 17 RC-Drives Cost-Optimized IGBT for Consumer Drive Application Case Temperature Profile during "20min" cycle Infineon RCD in I-pak IKU06N60R 100 RCD_GHS 90 RCD_QLS RCD_Heatsink 80 Washing 12 sec rotation 5 sec stop 12 sec reverse direction Rinsing ? Rinsing Spinning Termp (°C) RCD_Ambient 70 60 2:30 min 4:15 min 1:36 3.30 min i 50 11:35 min Pump waterout 40 30 20 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 Time (sec) Figure 11 Delta Case-Ambient Temperature Profile during "20min" cycle RC-Drives vs Competitor 2. Delta Tc,LS - Ta 70 Rinsing RC-Drives LS 60 Competitor2 LS Termp (°C) 50 Washing 12 sec rotation 5 sec stop 12 sec reverse direction Rinsing Spinning 40 30 Additional 15°C for the RC-Drives Pump waterout 20 Additional 10°C for the RC-Drives 10 0 0 100 200 300 400 500 600 700 800 Time (sec) Figure 12 18 900 1000 1100 1200 1300 1400 1500 1600 RC-Drives Cost-Optimized IGBT for Consumer Drive Application 7.2 Mounting and Cooling Consideration As a cost saving option for consumer drive, the RC-Drives are intended to be a replacement of bigger packages to provide good enough performance in the selected application. Below we provide examples of mounting options for both surface mount (DPAK) and straight leads (IPAK) versions. 7.2.1 Surface Mount This package version is normally found in low power system (up to 300W), were simple surface mount assembly (soldering + reflow) allows a good cost saving for the power section of the inverter. Output power is limited by the thermal resistance of the package mounted directly on the PCB (TjA up to 50 °C/W), and power dissipation / switch must be kept within 2W approx. In the example below (Figure 13) we compare a commercial board for refrigerator compressors to a 200W RC-Drives demoboard developed in-house for compressors, fans and pumps: Commercial 200 W compressor board – D²PAK RC-Drive demoboard - DPAK Figure 13 19 RC-Drives Cost-Optimized IGBT for Consumer Drive Application In order to improve the heat dissipation, thermal vias are realized in the PCB under the device case, in order to allow a better heat dissipation in case a heatsink is mounted on the opposite side of the board (Figure 14 and 15). The heatsink is insulated by Thermal foil. Figure 14: Thermal vias for an improved thermal design 20 RC-Drives Cost-Optimized IGBT for Consumer Drive Application Figure 15: Example of heatisink mounting 7.2.2. Straight Leads mounting Vertical insertion of straight leads packages are typically found in higher power systems (600~800W), were normally TO-220 FullPAK are used anchored to heatsink. Here the RCDrives in IPAK can replace such packages, but an insulation foil has to be used because the drain of the DPAK is not isolated. An example is provided in Figure 16, were the Electrolux board of a commercial AEG Washing machine is used to test different IPAK mounting concepts. 21 RC-Drives Cost-Optimized IGBT for Consumer Drive Application Figure 16: Commercial board with TO-220 FullPAK + clips To improve the mounting for the IPAK, the heatsink design was changed to allow clips screwing (Figure17). The angle of the clips is now optimized for the IPAK size and a uniform pressure of the device on the heatsink is achieved. Insulating foil is added. Against vibrations typical on a washing machine, bolts can be added to secure the clips. 22 RC-Drives Cost-Optimized IGBT for Consumer Drive Application Figure 17: Mounting the clips with nuts and bolts. Different heatsink / clips combinations are also showed in Figure 18 and 19: Figure 18: different Clips / heatsink / foil combination for mounting of the IPAK 23 RC-Drives Cost-Optimized IGBT for Consumer Drive Application Figure 19: no bolts are used in this case, but direct screwing on the Aluminum heatsink. 24 RC-Drives Cost-Optimized IGBT for Consumer Drive Application w w w . i n f i n e o n . c o m / i g b t s 25 Published by Infineon Technologies AG