Archive for the ‘Design Idea’ Category
Queens develops first photonic crystal for space
August 8th, 2009 | 
Author: ElectronicsWeekly.com (August 7, 2009) – Queen’s University Belfast has developed the first quasi-optical frequency selective surface (FSS) that can simultaneously filter both horizontally and vertically polarised sub-millimetre wave signals.
Posted in Design Idea | 
Tags: Copper, EADS Astrium, European Space Agency, Interference, Photonic Crystal, Queens University, Titanium | 
No Comments »
Design OVP circuitry for safe USB charging
EETASIA.com — While the infrastructure for plugging portable devices into the USB for datacom-with-power applications is fairly universal today, using the USB as a power source for direct powering or charging a battery isn’t necessarily foolproof. You’ll generally need over-voltage protection (OVP) circuitry; here’s what to consider in designing your discrete or IC-based circuit.
Posted in Design Idea |
Tags: connector, Li-ion battery, over voltage protection, OVP circuitry, USB charging |
2 Comments »
Quasiresonant flyback converter easily charges energy-storage capacitors
EDN.com — Designers often use chargers with flyback topologies to quickly charge energy-storage capacitors (reference 1 and reference 2). In a flyback topology, the energy transfer takes place only when the charger’s power MOSFET is off, which effectively isolates the power switch from the load, comprising high-energy storage-capacitor banks. Thus, the voltage levels on the circuit transformer’s secondary can vary from zero to a predetermined value and corresponding energy level without any significant stress on the components on the primary side of the transformer.