1. Development of DC/DC converter in VHF band Ivo Polák and Jiří Kvasnička on behalf of the BRAHMS project Institute of Physics of the ASCR, Na Slovance 2, CZ - 18221 Prague 8, Czech Republic, e-mail: polaki@fzu.cz TWEPP 2011, Wien, Austria Next steps Push – Pull generator (amplifier) at lower VHF band PWR 12W out Built to developing of RF rectifier circuitry We are testing toroidal inductor at PCB, for development of phase modulator. BRAHMS Principal schema Physica: cosmics or beam muons LED: flashes with small amplitude ● VHF versus traditional low MHz converters ● Small components, transmitter-RF types, small inductors and suppression elements ● Unique solution and design, DC-DC converters running at VHF are not often published Topology - Resonant system ● We are testing phase control of push - pull switch ● An option is the pulse on/off control, single ended VHF band (30MHz to 300MHz) Circuitry is in design procedure. Some Passive components were tested too, all survived with non or very little change of parameters. It includes: C – ceramic, foil MKP, LESR Alu, R – smd, wired, metallized Breadboarding - recent part of work – RF power ● Get new robust GAN technology (transistors, diodes ) to our lab ● Irradiate and measure larger scale of electronic components – analogue & logic ICs, OPA, comparators, varicaps ● Test of coaxial transformers → then PCB version ● Development of fast RF rectifiers (diode or active) References: 1. Architectures, Topologies, and Design Methods for Miniaturized VHF Power Converters, David J.Perreault, PwrSOC `08, Cork, Ireland Sept. 2008 2. A Very High Frequency dc-dc Converter Based on a Class Φ 2 Resonant Inverter, Juan M. Rivas, MIT, MA 3. http://shaktipower.sites.yale.edu Push-pull (2 phases) converter Output PWR is controlled by phase of input signals, there it is operated at 100MHz. Specification of module DC-DC converter Input voltage 200V DC (might be also different) ● Output voltage 3.3V, 5V and 15V ● Magnetic field ~20mT, test at 100mT ● Longterm operation at radiation ● operating frequency >20MHz, over the bandwidth of FEE (to suppress interference at FEE in detector) ● compactness ● Parameters are chosen to meet current requirements of HEP detector (inspiration: ATLAS TileCal) Air core inductor / transformer We are using part of techniques originally developed for CALICE at Prague Dual CH generator AFG, Can change phase between A and B Scope TDS5104 Stripline transformer on multilayer PCB is the target One of Experimental Transformers with coaxial cable ● Schottky diode can be used with low Output voltage (3.3V, 5V and up to ~15V) due to breakdown voltage and safety margin ● We tested schottky diode 1N5822 at lower VHF (~40MHz), efficiency seems to be higher. Better match is needed, more work to do. ● At operating frequency >100MHz, we need diode with lower internal C D to get resonance. ● Hard drive of fets is ineffective! Resonant system is efficient at VHF (UHF) ● Resonant transformer is a choice ● Resonant rectification (diode or active) Resonant rectification Resonant powertrain BRAHMS BRAHMS is a project for R&D of cost effective DC- DC module for radiation and magnetic enviroment, dedicated for HEP particle detector.