Abstract
Tells the development along with the electric power electronic technology, the electric power electronic installation and people's work, the life relations are day by day close, but the electronic installation cannot leave the reliable power source, has realized the switching power supply comprehensively since the 80s computer power source, takes the lead to complete computer's power source update, entered each kind of electronic, the electric appliance equipment domain one after another since the 90s switching power supply, the program controlled switch, the communication, the electron check-out facility power source, the control device power source and so on widely has used the switching power supply, promoted the switching power supply technology rapidly expand. The switching power supply is uses the modern electric power electronic technology, controlling switch transistor clear and the shutdown time ratio, the maintenance stable output voltage one kind of power source, the switching power supply (PWM) controls IC and the MOSFET constitution generally by the pulse width modulation. The switching power supply and the linear power source compare, the two's cost increases along with the output grows, but the two growth speed varies. The linear power source cost lights in some output, instead is higher than the switching power supply, this cost point of inversion. Along with the electric power electronic technology's development and the innovation, cause the switching power supply technology to innovate unceasingly, this cost point of inversion to the low output electric power end migration, this has provided the widespread development opportunities day by day for the switching power supply.
key word: Switching power supply constant voltage instantaneous voltage