High Temperature DC-DC Converter Performance Comparison Using SiC JFETs, BJTs and Si MOSFETs


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The performance and characterization of SiC JFETs and BJTs, used as inverter switching devices, in a 2 kW, high temperature, 33 kHz, 270-28 V DC-DC converter has been accomplished. SiC and Si power devices were characterized in a phase shifted H-bridge converter topology utilizing novel high temperature powdered ferrite transformer material, high temperature ceramic filter capacitors, SiC rectifiers, and 10 oz. 220oC polyimide printed circuit boards. The SiC devices were observed to provide excellent static and dynamic characteristics at temperatures up to 300oC. SiC JFETs were seen to exhibit on-resistance trends consistent with temperature-mobility kinetics and temperature invariant dynamic loss characteristics. SiC BJTs exhibited positive temperature coefficients (TCE) of VCE and negative β TCEs, with only a 2-fold increase in on-resistance at 300oC. Both SiC power devices possessed fast inductive switching characteristics with τon and τoff ~100-150 ns when driving the transformer load. The SiC converter characteristics were compared to Si-MOSFET H-bridge operation, over its functional temperature range (30-230oC), and highlights the superiority of SiC device technology for extreme environment power applications.



Materials Science Forum (Volumes 556-557)

Edited by:

N. Wright, C.M. Johnson, K. Vassilevski, I. Nikitina and A. Horsfall




J. D. Scofield et al., "High Temperature DC-DC Converter Performance Comparison Using SiC JFETs, BJTs and Si MOSFETs", Materials Science Forum, Vols. 556-557, pp. 991-994, 2007

Online since:

September 2007




[1] J. Scofield et. al.: presented at MRS spring meeting, April 17 - 21 2006 San Francisco CA.

[2] S. Krishnaswami et. al.: IEEE Electron Device Letters Vol 26 No 3 (2005), p.175.

[3] B. Ray et. al.: Proc. IEEE APEC Austin TX ( 2005), p.315.

[4] R. Spyker et. al.: Proc. IEEE APEC Austin TX (2005) pp.1275-350.


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[3] 5x10 -3 SiC JFET Turn-on SiC BJT Turn-on Si MOSFET Turn-on Turn-on Loss (J) Temperature ( o C) SiC JFET Turn-off SiC BJT Turn-off Si MOSFET Turn-off Turn-off Loss (J) 0 50 100 150 200 250 300 350 0 1 2 3 4 5 6 7 8 9 10 11.

DOI: 10.1142/9789813109414_0016



[1] 0.

[1] 5.

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[2] 5 SiC JFET, On-State SiC BJT, On-State T 3/2 resistivity trend Si MOSFET On-State Loss (W) Temperature ( o C) SiC JFET Off-State SiC BJT Off-State Si MOSFET Off-State Off-State Loss (W) Fig. 5. Static loss results for all devices in the test H-bridge, Conduction and reverse leakage. Fig. 6. Energy loss values for inverter switches.

DOI: 10.1109/tencon.2003.1273159

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