Technical Knowledge Transfer For Low Cost Buck Boost Converters

Today’s DC-to-DC converters efficiently step-up (Boost), step-down (Buck) or invert DC voltages without the need for a transformer. Typically switching capacitors are utilized and this reduces physical size requirements. They open up product size reduction, especially in portable electronic devices, where they increase efficiency and reduce input power for optional micro-power requirements. This further reduces heat, which can be a factor in numerous applications and even drives battery size reductions. Opportunities in battery charging and conditioning benefit greatly from this new technology. Good examples include the fast mobile phone and NiCAD battery chargers. Boost converters enable miniature fluorescent lights and high-intensity LED products powered by low voltages and occasionally only one 1.5 Volt dry-cell battery. Liquid Crystal Display (LCD) backlighting applications benefit from high frequency and multiple-output converters that drastically increase voltages. This paper discusses several DC-DC converter applications, capabilities, designs, technical specifications, limitations and some concentrated experimental findings with the boost converters. The focus will not be on the traditional 3-terminal converters or regulators, but on the favorable new technologies. Converter pros, cons and limitations and datasheets will be available as a reference. Primary and secondary side controllers such as fly back and forward converters are also available technologies. They can replace DC-to-DC converters in the proper applications while reducing cost. Supporting electronic component selection, mounting locations and connection distance importance are addressed and experimental data will be referenced. The buck-boost converters are sensitive, electrical noise generating and unstable if not properly designed in conjunction with supporting components and physical layout. Manufacturer application notes and Spice models narrow in on component specifications. Debugging and experimental key learning’s focus will be on the low-cost efficient boost converters. A suggested development path example for folks new to this area will follow Spice modeling, converter selection, prototype board selection, component purchasing, circuit building, debugging and power output improvement. This paper could provide a quick introduction into the buck-boost converter world.