Page 1APT9502LOW COST 1000 WATT, 300 VOLT RF POWERAMPLIFIER FOR 13.56 MHzPresented at RF EXPO EAST 1995APPLICATION NOTEAPT9502By Kenneth W. DierbergerPage 2APT9502Low Cost 1000 Watt, 300 Volt RF Power Amplifier for13.56MHzKenneth DierbergerLee B. MaxApplications Engineering ManagerIndependent ConsultantAdvanced Power Technology Inc.6284 Squiredell Dr.405 SW Columbia St.San Jose, California 95129 USABend, Oregon 97702 USABobby McDonaldUNI-WEST ENGINEERING6329 Bethel Island Rd.Bethel Island, CA 94511 USAABSTRACTThis paper details the design, development , assembly and performance of a low cost, high-efficiency,1000Watt, 13.56MHz RF power amplifier (PA) operated from a 300VDC supply, with an efficiency of80%. The PA is built around a “symmetric Pair” of low cost RF power MOSFETs from AdvancedPower Technology (APT). The transistors are from a new generation of high quality, commercial, HF/VHF, silicon, 900V RF power MOSFETs in TO-247 packages. The paper addresses both the theoreticaldesign and physical construction of the amplifier. The paper also contains a technical description ofthe RF power transistors.INTRODUCTIONMost transistorized RF Power Amplifiersoperate from a DC to DC converter. This supplyis usually low voltage, about 50V, and requires adown regulator when operated from AC mains.This converter is a significant portion of the overallcost of the RF amplifier system.As a result of IEC555-2, all electronicequipment sold in Europe with a power draw ofgreater than 250W will require power factorcorrection (PFC). The addition of a PFCpreregulator to the system could add 50 to 100%to the cost of the power supply portion. Therequirement for PFC is soon to follow in the USAand the rest of the world.Page 3APT9502The use o...
