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A power supply is a buffer circuit that provides power with the characteristics required by the load from a primary power source with characteristics incompatible with the load. It makes the load compatible with its power source. Example: A power source might be the 60 Hz, single phase, 120 V ac power found in a home in the United States or the 50 Hz, single phase, 220 V ac found in the United Kingdom. The load might be a logic circuit in a personal computer that requires regulated 5 V dc power. The power supply is the circuit that makes the 120 V ac or 220 V ac power source and 5 V dc load compatible.
A power supply is sometimes called a power converter and the process is called power conversion. It is also sometimes called a power conditioner and the process is called power conditioning. The Power Sources Manufacturers Association's (PSMA) Handbook of Standardized Terminology for the Power Sources Industry gives this definition of a power supply. Power Supply -- A device for the conversion of available power of one set of characteristics to another set of characteristics to meet specified requirements. Typical application of power supplies include to convert raw input power to a controlled or stabilized voltage and/or current for the operation of electronic equipment.
Power supplies belong to the field of power electronics, the use of electronics for the control and conversion of electrical power. The IEEE Power Electronics Society provides a more formal definition of power electronics in their constitution. Power Electronics -- This technology encompasses the effective use of electronic components, the application of circuit theory and design techniques, and the development of analytical tools toward efficient electronic conversion, control, and conditioning of electric power.
A switching-mode power supply is a power supply that provides the power supply function through low loss components such as capacitors, inductors, and transformers -- and the use of switches that are in one of two states, on or off. The advantage is that the switch dissipates very little power in either of these two states and power conversion can be accomplished with minimal power loss, which equates to high efficiency. The term switchmode was widely used for this type of power supply until Motorola, Inc., who used the trademark SWITCHMODE TM for products aimed at the switching-mode power supply market, started to enforce their trademark. Then more generic terms had to be found. I started using the term switching-mode power supply to avoid infringing on the trademark. Others used the term switching power supply, which seems to be the more popular term. PSMA does not define either switching-mode power supply or switching power supply, but does define switching regulator. Switching Regulator -- A switching circuit that operates in a closed loop system to regulate the power supply output.
Editor: Jerrold Foutz |
