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This paper presents a measurement setup for pulsed RF characterization of a buck-converter-based envelope tracking (ET) system. In contrast to continuous wave (CW) measurements, the proposed method allows ET system characterization over its full dynamic range without exceeding the power dissipation safe operating area. It includes the dynamic characterization of the individual subsystems, i.e., the...
This paper presents a wideband supply-modulated system with a floating ground RF power amplifier and a reverse buck topology DC/DC converter. The power amplifier and the reverse buck converter are based on microwave GaN technology. The system is operating at 1620 MHz and 40 V supply and shows 39% overall power-added efficiency at an average output power of 14.6 W for an 8 MHz OFDM modulated signal...
Power MOSFETs have been primarily designed for switching applications, in which case they are operated to the best extent possible either at zero drain to source voltage or at zero drain current. Accordingly, datasheets provide parametric information including input, output and reverse parasitic capacitance at zero current level. When used in linear condition however, both drain to source voltage...
This paper presents two buck converters switching at 50 MHz and based on Gallium Nitride dice. The first converter features a diode designed for power applications and demonstrates 87.9% peak efficiency. The diode mounted on the second one is aimed at higher-frequency operation and brings this value up above 91% in the same operating conditions. Loss contributions are evaluated, showing the influence...
An experimental VHF DC/DC converter aimed at envelope-tracking amplifiers for space applications is presented. Based on Gallium Nitride components, it is capable of operating in the range of tens of watts, as required by on-board transmitters. When driven by a 50-MHz PWM signal, it reaches a peak efficiency of 91.6%. A detailed breakdown of the associated losses is reported in order to identify the...
The Gallium Nitride semiconductor technology allows switching operation at high frequency and supports voltage levels compatible with medium power applications. Its emergence has resulted in a number of works investigating the feasibility of high frequency DC/DC converter prototypes primarily in terms of efficiency. The present paper goes one step beyond and reports electromagnetic emission measurements,...
The compliance to the fault tolerant operation requirement for power electronics is commonly assessed with reference to fault models applicable at component level. For switching MOSFET, the fault models include the short-circuit and open-circuit failures, implicitly assuming that the Gate open failure is equivalent to a switch open or short failure. MOSFET Gate open failure, also called floating Gate...
This paper describes a fast envelope-tracking circuit capable of 10 MHz (up to 17.5 MHz) bandwidth based on RF GaN switching devices and 50 MHz switching frequency. The efficiency of the VHF converter is 84% to 90% which is comparable to a conventional DC/DC converter for spaceborne application. A demonstrator has been built and mated with a RF GaN HEMT output stage. The C/I measurement for 10–12W...
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