Approximate efficiency of a linear regulator is given by the ratio of regulated output voltage to input voltage. Higher voltage difference between the input and the output means a lower efficiency due to heavy losses in the series power semiconductor. Supercapacitor-assisted low dropout regulator (SCALDO) is an emerging linear DC-DC converter technique, where a supercapacitor (SC) is used to reduce the voltage drop across the series transistor in a linear regulator where the SC acts as a lossless dropper. The circuit operates at a very low frequency decided by the size of the SC. An efficiency multiplication factor such as 1.33, 2, or 3 is achieved depending on the configuration. This study presents the essentials of its generalised theory, few prototype implementations, and a discussion on SCALDO properties. Typical efficiencies of 12-5 and 5-1.2 V linear regulators are around 42 and 24%, respectively. When SCALDO prototypes are built, the authors achieve respective end-to-end efficiencies of 79-81 and 58-73%. A loss analysis summary and further developments of the novel technique are also provided, in addition to a discussion to indicate that this is not a variation of the switched capacitor converters. cycle time >1,
All electrical and electronic devices require access to a suitable energy source. In a portable electronic product, such as a cell phone, an energy storage unit drives a complex array of power conversion stages to generate multiple DC voltage rails required. To optimize the overall end-to-end efficiency, these internal power conversions should waste minimal energy and deliver more to the electronic modules. Capacitors are one of the main component families used in electronics, to store and deliver electric charges. Supercapacitors, so called because they provide over a million-fold increase in capacitance relative to a traditional capacitor of the same volume, are enabling a paradigm shift in the design of power electronic converter circuits. Here we show that supercapacitors could function as a lossless voltage-dropping element in the power conversion stages, thereby significantly increasing the power conversion stage efficiency. This approach has numerous secondary benefits: it improves continuity of the supply, suppresses voltage surges, allows the voltage regulation to be electromagnetically silent, and simplifies the design of voltage regulators. The use of supercapacitors allows the development of a novel loss-circumvention theory with applicability to a wide range of supercapacitor-assisted (SCA) techniques. These include low-dropout regulators, transient surge absorbers, LED lighting for DC microgrids, and rapid energy transfer for water heating.
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