High-frequency switching powerSupply circuit of high frequency switching power supply from the following components : first. a main circuit from the exchange network input, DC output of the entire process, including : an import filter : its role is to network the clutter filtration, but also hindered the plane of the clutter feedback to the public grid. 2, rectifier and filter : direct AC power rectifier for smoother DC, for under a transformation. 3, the inverter : Rectifier the high frequency alternating current into direct current, high-frequency switching power supply is the core component of the higher frequency, size, weight and output ratio smaller. 4, and the rectifier output filter : Under load the need to provide stable and reliable DC power supply. Second, the control circuit while output from the sample, with the set standards, then controlled inverter, change its frequency or pulse width output achieve stability, on the other hand, according to test data provided by the circuit by circuit protection identification, Control circuit for the unit for various protection measures. Third, in addition to providing detection circuit protection circuit is running various parameters, but also provide information display instruments. Fourth, the auxiliary power supply circuit for the single power supply to the different requirements.Switching regulator control principleSwitching Control Switching Regulators K principle to a certain time interval repeatedly connected and disconnected, connected to the switch K, Input voltage E and K through switching circuit filter to load RL, the entire switch connected, Power E to provide energy load; When K disconnect switch, the input power is interrupted E. energy delivery. This shows that the importation of power to provide energy load is intermittent, for the load can be provided for the energy, Switching power supply must be a set of storage devices, the switches will be connected to a part of the energy stored in the switch disconnected. Load to the release. Map from the inductance L, capacitance diode D and C2 components of the circuit, it is such a function. Inductor L for energy storage in switch disconnected, stored in the inductor L of energy release through diodes D to load, so that load is continuous and stable energy, diode D enable continuous load current, known as the continued flow diode. AB in the average voltage EAB can be given by : EAB=TON/T*E where TON connected to the switch each time, T-off switch for the cycle (that is, access time TON switch and turn-off time and TOFFs). - We can see from the change switch connected to the work cycle time and the ratio of the voltage between the AB average change also, therefore, With the load and input supply voltage changes and automatically adjust TON T ratio, it will cause the output voltage V0 unchanged. Change the access time and cycle TON percentage change is the pulse duty cycle. This method, known as time ratio control (Time Ratio Control, for the initials TRC). TRC under control principle, there are three ways : 1. Pulse width modulation (Pulse Width Modulation, acronym for PWM) switching constant cycle by changing the pulse width to change the duty cycle approaches. 2, pulse frequency modulation (Pulse Frequency Modulation, acronym for the PFM) conduction pulse width constant by changing the switching frequency to change the duty cycle approaches. 3, mixed conduction modulation and pulse width switching frequency not fixed are, they change the way It is more than two hybrid models. SMPS developments and trends in the United States in 1955 Roje (GH.Roger) invention of the self-excited oscillation push redeem transistor single transformer DC converters, high-frequency conversion is the beginning of control circuit, 1957 United States investigation tournament (Jen Sen) since the invention of the push-pull double Flyback transformers, 1964 American scientists proposes to abolish the frequency transformer series switching power supply scenario, This power to the right size and weight of the decline was a fundamental way. To the 1969 high-power silicon transistor because the pressure increase diode reverse recovery time shortened, and other components improve, and finally turned into a 25 kHz switching power supply. Currently, switching power supply to small, Light volume and the characteristics of high efficiency has been widely used in electronic computer-driven variety of terminal equipment, Communications equipment almost all electronic equipment, the electronic information industry indispensable to the rapid development of a power mode. Currently the market for sale in the switching power supply using bipolar transistors made of 100kHz. use made of 500kHz MOS power, though practical, but its frequency to be further enhanced. To improve the switching frequency, it is necessary to reduce the switching loss, and to reduce the switching loss, you need to have high-spee