Novel GaAs Switch for Compact and Efficient Power Conversion

Mariam Sadaka, Sriram Chandrasekaran, Al Rozman*
ColdWatt Inc., 13809 Research Blvd., Suite 475, Austin TX 78750
*ColdWatt Inc., 820 F Ave., Suite 104, Plano TX 75074, mariam.sadaka@coldwatt.com
Wonill Ha, Bobby Brar, Chanh Nguyen, Vivek Mehrotra
Teledyne Scientific and Imaging, 1049 Camino Dos Rios, Thousand Oaks, CA 91360
Peter Asbeck
Department of Electrical and Computer Engineering , 9500 Gilman Drive, Mail Code 0407, University of
California, San Diego, La Jolla, CA 92093
Keywords: pHEMT, Power switch, High current capability, Low on-resistance, Cost effective
Abstract
The development and demonstration of a novel GaAs switch called Substrate-Driven FET (SDFET) is reported in this paper. The SD-FET process is compatible with standard large volume pHEMT processes and the device has far superior switching properties compared to state-of-the-art Si devices. This combination of cost effectiveness and excellent performance makes the SD-FET vital for meeting the challenging power requirements of next generation portable applications. Devices with current capability of 20A with a gate width of 1 meter, specific onresistance of 0.26mW-cm2, and turn-on and turnoff transitions less than 1nsec have been demonstrated. Power losses due to conduction, gate charge, output capacitance and switching transitions are lower than that of commercially available state-of-the-art Si devices, thereby validating the capability of the SD-FET in enabling compact and highly efficient power conversion. The performance of the SD-FET in a multiphase buck converter application was analyzed showing at least 9 percentage points improvement in efficiency over an equivalently rated Si-based counterpart.
 
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