Research

Academic/Research and Field Interests:

  • Analog/Mixed-Signal Integrated Circuit Design
  • Analog/Mixed-Signal IC Design for Extreme Environments
  • Ultra Low Voltage CMOS IC Design
  • Multi-gate transistors and circuit applications
  • Bio-microelectronics

Our current research focus includes analog IC design for extreme environments, mixed-signal/mixed-voltage circuit design for systems-on-a-chip in SOI technology, multi-gate transistors and circuits on SOI, body-driven circuit techniques for ultra low-voltage CMOS analog, and bio-microelectronics.

Recent Journal Articles:

  • Z. Zhang, J. Dix; F. F. Wang, B. J. Blalock, D. J. Costinett, and L. M. Tolbert, “Intelligent Gate Drive for Fast Switching and Crosstalk Suppression of SiC Devices,” IEEE Trans. on Power Electronics, vol. 32, no. 12, December 2017, pp. 9319-9332.
  • Z. Zhang, B. Guo, F. F. Wang, E. A. Jones, L. M. Tolbert, and B. J. Blalock, “Methodology for Wide Band-Gap Device Dynamic Characterization,” IEEE Trans. on Power Electronics, vol. 32, no. 12, December 2017, pp. 9307-9318
  • Z. Zhang, H. Lu, D. J. Costinett, F. Wang, L. M. Tolbert, and B. J. Blalock, “Model-Based Dead Time Optimization for Voltage-Source Converters Utilizing Silicon Carbide Semiconductors,” IEEE Trans. on Power Electronics, vol. 32, no. 11, November 2017, pp. 8833-8844.
  • M. S. Hasan, T. Rahman, S. K. Islam, and B. Blalock, “Numerical Modeling and Implementation in Circuit Simulator of SOI four-gate transistor (G4FET) Using Multidimensional Lagrange and Bernstein Polynomial,” Microelectronics Journal, vol. 65, July 2017, pp. 83-93. 
  • Y. Cui, F. Yang, L. M. Tolbert, D. J. Costinett, F. Wang, and B. J. Blalock, “Load Dependent Soft Switching Method of Half Bridge Current Doubler for High Voltage Point of Load Converter in Data Center Power Supplies,” IEEE Trans. on Power Electronics, vol. 32, no. 4, April 2017, pp. 2925-2938.
  • W. Zhang, F. Wang, D. J. Costinett, L. M. Tolbert, B. J. Blalock, “Investigation of Gallium Nitride Devices in High-Frequency LLC Resonant Converters,” IEEE Trans. on Power Electronics, vol. 32, no. 1, January 2017, pp. 571-583.
  • Z. Wang, X. Shi, L. M. Tolbert, F. Wang, and B. Blalock, “Temperature Dependent Short Circuit Capability of Silicon Carbide (SiC) Power MOSFETs,” IEEE Trans. on Power Electronics, vol. 31, no. 2, February 2016, pp. 1555-1566.
  • F. Xu, B. Guo, Z. Xu, L. M. Tolbert, F. Wang, and B. J. Blalock, “Paralleled Three-Phase Current-Source Rectifiers for High-Efficiency Power Supply Applications,” IEEE Transactions on Industrial Applications, vol. 51, no. 3, 2015, pp. 2388-2397
  • Z. Zhang, F. Wang, L. M. Tolbert, B. J. Blalock, and D. J. Costinett, “Evaluation of Switching Performance of SiC Devices in PWM Inverter Fed Induction Motor Drives,” IEEE Transactions on Power Electronics, vol. 30, no. 10, 2015, pp. 5701-5711
  • Z. Wang, X. Shi, L. M. Tolbert, F. Wang, Z. Liang, D. Costinett, B. J. Blalock, “A High Temperature Silicon Carbide MOSFET Power Module With Integrated Silicon-On-Insulator-Based Gate Drive,” IEEE Transactions on Power Electronics, vol. 30, no. 3, 2015, pp. 1432-1445.
  • Z. Wang, X. Shi, Y. Xue, L. M. Tolbert, F. Wang, and B. J. Blalock, “Design and Performance Evaluation of Overcurrent Protection Schemes for Silicon Carbide (SiC) Power MOSFETs,” IEEE Transactions on Industrial Electronics, vol. 61, no. 10, 2014, pp. 5570-5581.
  • Z. Wang, X. Shi, L. M. Tolbert, F. Wang, and B. J. Blalock, “A di/dt Feedback-Based Active Gate Driver for Smart Switching and Fast Overcurrent Protection of IGBT Modules,” IEEE Transactions on Power Electronics, vol. 29, no. 7, 2014, pp. 3720-3732.
  • Z. Zhang, F. Wang, L. M. Tolbert, and B. J. Blalock, “Active Gate Driver for Crosstalk Suppression of SiC Devices in a Phase-Leg Configuration,” IEEE Transactions on Power Electronics, vol. 29, no. 4, 2014, pp. 1986-1997.
  • P. C. Adell, J. Yager, Z. Pannell, J. Shelton, M. M. Mojarradi, B. Blalock, G. Allen, R. Some, “Radiation Hardening of an SiGe BiCMOS Wilkinson ADC for Distributed Motor Controller Application,” IEEE Transactions on Nuclear Science, vol. 61, no. 3, 2014, pp. 1236-1242.
  • F. Xu, B. Guo, L. M. Tolbert, F. Wang, and B. J. Blalock, “An All-SiC Three-Phase Buck Rectifier for High Efficiency Data Center Power Supplies,” IEEE Transactions on Industry Applications, vol. 49, no. 6, 2013, pp. 2662-2673.
  • B. M. McCue, B. J. Blalock, C. L. Britton, J. Potts, J. Kemerling, K. Isihara, and M. T. Leines, “A Wide Temperature, Radiation Tolerant, CMOS-Compatible Precision Voltage Reference for Extreme Radiation Environment Instrumentation Systems,” IEEE Transactions on Nuclear Science, vol. 60, no. 3, 2013, pp. 2272-2279.
  • K. Tham, C. Ulaganathan, N. Nambiar, R. L. Greenwell, C. L. Britton, M. N. Ericson, J. Holleman, and B. J. Blalock, “PVT Compensation for Wilkinson Single-Slope Measurement Systems,” IEEE Transactions on Nuclear Science, vol. 59, no. 5, part 3, 2012, pp. 2444-2450.
  • M. A. Huque, S. K. Islam, L. M. Tolbert, and B. J. Blalock, “A 200°C Universal Gate Driver Integrated Circuit for Extreme Environment Applications,” IEEE Transactions on Power Electronics, vol. 27, no. 9, 2012, pp. 4153-4162.
  • L. Zuo, R. Greenwell, S. K. Islam, M. A. Huque, B. J. Blalock, and L. M. Tolbert, “A Universal SOI-Based High Temperature Gate Driver Integrated Circuit For SiC Power Switches With On-Chip Short Circuit Protection,” International Journal of High Speed Electronics and Systems (IJHSES), vol. 20, no. 3, 2011, pp. 471-484.
  • S. A. Eliza, S. K. Islam, T. Rahman, N. D. Bull, B. J. Blalock, L. R. Baylor, M. N. Ericson, and W. L. Gardner, “A Precision Dose Control Circuit for Maskless E-Beam Lithography With Massively Parallel Vertically Aligned Carbon Nanofibers,” IEEE Transactions on Instrumentation and Measurement, vol. 60, no. 4, Apr. 2011, pp. 1132-1140.
  • C. Ulaganathan, N. Nambiar, K. Cornett, R. L. Greenwell, J. A. Yager, Be. S. Prothro, K. Tham, S. Chen, R. S. Broughton, G. Fu, B. J. Blalock, C. L. Britton Jr., M. N. Ericson, H. A. Mantooth, M. M. Mojarradi, R. W. Berger, and J. D. Cressler “A SiGe BiCMOS Instrumentation Channel for Extreme Environment Applications,” Hindawi Journal of VLSI Design, Vol. 2010, Article ID 156829, 12 pages.
  • M. A. Huque, L. M. Tolbert, B. J. Blalock, S. K. Islam, “Silicon-on-Insulator-Based High-Voltage, High-Temperature Integrated Circuit Gate Driver for SiC-Based Power FETs,” IET Proceedings on Power Electronics, vol. 3, issue 6, 2010, pp. 1001-1009.
  • N. Nambiar, B. J. Blalock, and M. Nance Ericson, “A Novel Current-Mode Multi-Channel Integrating ADC,” Journal of Analog Integrated Circuits and Signal Processing, vol. 63, issue 2, May 2010, pp. 283-291.

Recent Conference Papers:

  • J. Sangid, G. Long, P. Mitchell, B. J. Blalock, D. J. Costinett and L. M. Tolbert, "Comparison of 60V GaN and Si Devices for Class D Audio Applications," 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA), Atlanta, GA, 2018, pp. 73-76.
  • G. Gabian, J. Gamble, B. J. Blalock, and D. Costinett, “Hybrid Buck Converter Optimization and Comparison for Smart Phone Integrated Battery Chargers,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 4-8, 2018, San Antonio, Texas, pp. 2148-2154.
  • R. Chen, Z. Zhang, R. Ren, J. Niu, H. Gui, F. Wang, L. M. Tolbert, D. J. Costinett, and B. J. Blalock, “Common-Mode Noise Reduction with Impedance Balancing in DC-Fed Motor Drives,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 4-8, 2018, San Antonio, Texas, pp. 2515-2520.
  • Z. Zhang, H. Gui, J. Niu, R. Chen, F. Wang, L. M. Tolbert, D. J. Costinett, and B. J. Blalock, “High Precision Gate Signal Timing Control Based Active Voltage Balancing Scheme for Series-Connected Fast Switching Field-Effect Transistors,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 4-8, 2018, San Antonio, Texas, pp. 925-930. 
  • R. Chen, Z. Zhang, R. Ren, J. Niu, H. Gui, F. Wang, L. M. Tolbert, D. J. Costinett, and B. J. Blalock, “Common-Mode Inductor Saturation Analysis and Design Optimization based on Spectrum Concept,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 4-8, 2018, San Antonio, Texas, pp. 2583-2588.
  • J. Dyer, Z. Zhang, F. Wang, D. Costinett, L. M. Tolbert, and B. J. Blalock, “Online Condition Monitoring based Dead-Time Compensation for High Frequency SiC Voltage Source Inverter,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 4-8, 2018, San Antonio, Texas, pp. 1854-1860.
  • Y. Cui, L. M. Tolbert, D. J. Costinett, F. Wang, and B. J. Blalock, “Direct 400 Vdc to 1 Vdc Power Conversion with Input Series Output Parallel Connection for Data Center Power Supplies,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 4-8, 2018, San Antonio, Texas, pp. 1554-1560.
  • J. Dyer, Z. Zhang, F. Wang, D. Costinett, L. Tolbert, and B. J. Blalock, “Dead-Time Optimization for SiC based Voltage Source Converters using Online Condition Monitoring,” 2017 IEEE Workshop on Wide Bandgap Power Devices and Applications (WiPDA), Oct. 30-Nov. 1, 2017, Albuquerque, New Mexico, pp. 15-19.
  • G. Gabian, J. Gamble, B. Blalock, and D. Costinett, “Modeling High Current Integrated Power Converters,” 2017 IEEE 18th Workshop on Control and Modeling for Power Electronics (COMPEL), July 9-12, 2017, Padova, Italy, pp. 1-7.
  • Z. Zhang, C. Timms, J. Tang, R. Chen, J. Sangid, F. Wang, L. M. Tolbert, B. J. Blalock, D. J. Costinett, “Characterization of High-Voltage High-Speed Switching Power Semiconductors for High Frequency Cryogenically-Cooled Application,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 26-30, 2017, Tampa, Florida, pp. 1964-1969.
  • W. Zhang, Z. Zhang, F. Wang, D. Costinett, L. Tolbert, and B. Blalock, “Common Source Inductance Introduced Self-Turn-On in MOSFET Turn-Off Transient,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 26-30, 2017, Tampa, Florida, pp. 837-842.
  • G. Gabian, B. Blalock, and D. Costinett, “5V-to-4V Integrated Buck Converter for Battery Charging Applications with an On-Chip Decoupling Capacitor,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 26-30, 2017, Tampa, Florida, pp. 178-183.
  • J. Dyer, Z. Zhang, F. Wang, D. Costinett, L. M. Tolbert, and B. J. Blalock, “Online Condition Monitoring of SiC devices Using Intelligent Gate Drive for Converter Performance Improvement,” 2016 IEEE Workshop on Wide Bandgap Power Devices and Applications (WiPDA), Nov. 7-9, 2016, Fayetteville, Arkansas, pp. 182-187.
  • Z. Zhang, F. Wang, D. J. Costinett, L. M. Tolbert, B. J. Blalock, and X. Wu, “Online Junction Temperature Monitoring Using Turn-Off Delay Time for Silicon Carbide Power Devices,” 2016 IEEE Energy Conversion Congress and Exposition (ECCE), Sept. 18-22, 2016, Milwaukee, Wisconsin, pp. 1-7.
  • R. K. Harris, B. M. McCue, B. D. Roehrs, C. Roberts, B. J. Blalock, D. J. Costinett, K. Sariri, G. Megyei, C.-P. Chen, A. Kashyap, and R. Ghandi, “A Silicon Carbide Integrated Circuit Implementing Nonlinear-Carrier Control for Boost Converter Applications,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 20-24, 2016, Long Beach, California, pp. 3255-3258.
  • J. Dix, Z. Zhang, and B. J. Blalock, “CMOS Gate Drive IC with Embedded Cross Talk Suppression Circuitry for SiC Devices,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 20-24, 2016, Long Beach, California, pp. 684-691.
  • Y. Cui, W. Zhang, L. M. Tolbert, D. J. Costinett, F. Wang, and B. J. Blalock, “Soft Switching for Half Bridge Current Doubler for High Voltage Point of Load Converter in Data Center Power Supplies,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 20-24, 2016, Long Beach, California, pp. 893-898.
  • Z. Zhang, F. Wang, L. M. Tolbert, B. J. Blalock, and D. J. Costinett, “Decoupling of Interaction Between WBG converter and Motor Load for Switching Performance Improvement,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 20-24, 2016, Long Beach, California, pp. 1569-1576.
  • Z. Zhang, F. Wang, L. M. Tolbert, B. J. Blalock, D. J. Costinett, “Realization of High Speed Switching of SiC Power Devices in Voltage Source Converters,” 2015 IEEE Workshop on Wide Bandgap Power Devices and Applications (WiPDA), Nov. 2-4, 2015, Blacksburg, Virginia, pp. 28-33.
  • Z. Zhang; Z. Wang, F. Wang, L. M. Tolbert, B. J. Blalock, “Reliability-Oriented Design of Gate Driver for SiC Devices in Voltage Source Converter,” IEEE International Workshop on Integrated Power Packaging (IWIPP), May 3-6, 2015, Chicago, Illinois, pp. 20-23.
  • Z. Zhang, F. Wang, D. J. Costinett, L. M. Tolbert, B. J. Blalock, and H. Lu, “Dead-Time Optimization of SiC devices for Voltage Source Converter,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 15-19, 2015, Charlotte, North Carolina, pp. 1145-1152.
  • Yu Long, W. Zhang, D. Costinett, B. Blalock, and L. Jenkins, “A High-Frequency Resonant Gate Driver for Enhancement-Mode GaN Power Devices,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 15-19, 2015, Charlotte, North Carolina, pp. 1961-1965.
  • Z. Zhang, F. Wang, L. M. Tolbert, B. J. Blalock, and D. J. Costinett, “Active Gate Driver for Fast Switching and Cross-Talk Suppression of SiC Devices in a Phase-Leg Configuration,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 15-19, 2015, Charlotte, North Carolina, pp. 774-781.
  • W. Zhang, Y. Cui, F. Wang, L. M. Tolbert, B. J. Blalock, and D. J. Costinett, “Investigation of Gallium Nitride Devices Benefits on LLC Resonant DC-DC Converter,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 15-19, 2015, Charlotte, North Carolina, pp. 146-153.
  • Y. Cui, W. Zhang, L. M. Tolbert, D. J. Costinett, F. Wang, and B. J. Blalock, “Efficiency Impact of MOSFET Output Junction Capacitance on a High Step Down Ratio Phase Shift Full Bridge DC/DC Converter,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 15-19, 2015, Charlotte, North Carolina, pp. 2083-2089.
  • Y. Cui, W. Zhang, L. M. Tolbert, D. J. Costinett, F. Wang, and B. J. Blalock, “Two Phase Interleaved ISOP Connected High Step Down Ratio Phase Shift Full Bridge DC/DC Converter with GaN FETs,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 15-19, 2015, Charlotte, North Carolina, pp. 1414-1419.
  • W. Zhang, B. Guo, F. Xu, Y. Cui, Y. Long, F. Wang, L. M. Tolbert, B. J. Blalock, and D. Costinett, “Wide Bandgap Power Devices Based High Efficiency Power Converters for Data Center Application,” 2014 IEEE Workshop on Wide Bandgap Power Devices and Applications (WiPDA), Oct. 13-15, 2014, Knoxville, Tennessee, pp. 121-126.
  • Z. Zhang, F. Wang, L. M. Tolbert, B. J. Blalock, and D. Costinett, “Understanding the Limitations and Impact Factors of Wide Bandgap Devices’ High Switching-Speed Capability in a Voltage Source Converter,” 2014 IEEE Workshop on Wide Bandgap Power Devices and Applications (WiPDA), Oct. 13-15, 2014, Knoxville, Tennessee, pp. 7-12.
  • Y. Xue, J. Lu, Z. Wang, L. M. Tolbert, B. J. Blalock, and F. Wang, “A Compact Planar Rogowski Coil Current Sensor for Active Current Balancing of Parallel-Connected Silicon Carbide MOSFETs,” 2014 IEEE Energy Conversion Congress and Exposition (ECCE), Sept. 14-18, 2014, Pittsburgh, Pennsylvania, pp. 4685-4690.
  • Z. Wang X. Shi, L. M. Tolbert, F. Wang, Z. Liang, D. Costinett, and B. J. Blalock, “A High Temperature Silicon Carbide MOSFET Power Module with Integrated Silicon-on-Insulator Based Gate Drive,” 2014 IEEE Energy Conversion Congress and Exposition (ECCE), Sept. 14-18, 2014, Pittsburgh, Pennsylvania, pp. 4373-4380.
  • W. Zhang, F. Wang, L. M. Tolbert, B. J. Blalock, and D. Costinett, “Investigation of Soft-Switching Behavior of 600 V Cascode GaN HEMT,” 2014 IEEE Energy Conversion Congress and Exposition (ECCE), Sept. 14-18, 2014, Pittsburgh, Pennsylvania, pp. 2865-2872.
  • Z. Zhang, F. Wang, L. M. Tolbert, B. J. Blalock, D. Costinett, “Evaluation of Switching Performance of SiC Devices in PWM Inverter Fed Induction Motor Drives,” 2014 IEEE Energy Conversion Congress and Exposition (ECCE), Sept. 14-18, 2014, Pittsburgh, Pennsylvania, pp. 1597-1604.
  • Y. Long, W. Zhang, B. J. Blalock, L. M. Tolbert, and F. Wang, “A 10-MHz resonant gate driver design for LLC resonant DC-DC converters using GaN devices,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 16-20, 2014, Fort Worth, Texas, pp. 2093-2097.
  • Z. Xu, W. Zhang, F. Xu, F. Wang, L. M. Tolbert, B. J. Blalock, “Investigation of 600 V GaN HEMTs for High Efficiency and High Temperature Applications,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 16-20, 2014, Fort Worth, Texas, pp. 131-136. 
  • F. Xu, B. Guo, Z. Xu, L. M. Tolbert, F. Wang, and B. J. Blalock, “High Efficiency Paralleled Three-Phase Current Source Front-End Rectifiers for Data Center Power Supplies with Current Balancing and Hot-Swap,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 16-20, 2014, Fort Worth, Texas, pp. 900-905. 
  • Y. Xue, L. Junjie, Z. Wang, L. M. Tolbert, B. J. Blalock, and F. Wang, “Active Compensation of Current Unbalance in Paralleled Silicon Carbide MOSFETs,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 16-20, 2014, Fort Worth, Texas, pp. 1471-1477. 
  • Z. Zhang, B. Guo, F. Wang, L. M. Tolbert, B. J. Blalock, Z. Liang, and P. Ning,  “Methodology for Switching Characterization Evaluation of Wide Band-gap Devices in a Phase-leg Configuration,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 16-20, 2014, Fort Worth, Texas, pp. 2534-2541. 
  • Z. Zhang, B. Guo, F. Wang, L. M. Tolbert, B. J. Blalock, Z. Liang, and P. Ning, “Impact of Ringing on Switching Losses of Wide Band-gap Devices in a Phase-leg Configuration,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 16-20, 2014, Fort Worth, Texas, pp. 2542-2549. 
  • Y. Cui, F. Xu, W. Zhang, B. Guo, L. M. Tolbert, F. Wang, B. J. Blalock, L. L. Jenkins, C. G. Wilson, J. M. Aggas, B. K. Rhea, J. D. Moses, and R. N. Dean, “High Efficiency Data Center Power Supply Using Wide Band Gap Power Devices,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 16-20, 2014, Fort Worth, Texas, pp. 3437-3442. 
  • Y. Cui, W. Zhang, L. M. Tolbert, F. Wang, and B. J. Blalock, “Direct 400 V to 1 V Converter for Data Center Power Supplies Using GaN FETs,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 16-20, 2014, Fort Worth, Texas, pp. 3460-3464. 
  • B. Guo, F. Xu, F. Wang, L. M. Tolbert, and B. J. Blalock, “Overvoltage Protection Scheme for Three-Phase Current Source Converter Built with SiC MOSFETs,” IEEE Applied Power Electronics Conference and Exposition (APEC), March 16-20, 2014, Fort Worth, Texas, pp. 3469-3476.