【正文】 automation EDA technology appearance, we definitely may not need any electric circuit template the electric circuit which at home may design through the programming conforms to us to request to e using the puter, after but will design the electric circuit template will give the electronic factory to produce. The function is more perfect not only using the EDA technical design electric circuit, moreover the electric circuit exterior structure is simpler, the volume very is small even only is a scrap integrated circuit, and such circuit design energy consumption is very small conforms to us pletely to the energy conservation request. The semiconductors within a power factor correction stage have some special requirements. First, the 50/60 Hz rectifiers now have to be ultra fast rectifiers, since fast current pulses are being drawn through them. The boost output rectifier will have to be ultra fast if the boost converter is operating in the continuousmode. The power switch has to clear the diode’s reverse recovery charge. In the discontinuousmode (Pin 200 watts), the output rectifier need not be ultra fast since there is no current flowing through the diode prior to the power switch turning on.Such modern electric power electronic technology is the switching power supply technological development foundation. And it is suitable for the higher turnon frequency along with the new electric power electronic device the electric circuit analysis unceasing appearance. Under traditional application technology, because the switching power supply as a result of the power ponent performance limit the performance to e under the influence. In order to enormously displays each kind of power ponent the characteristic. Causes the ponent performance to start out from opposite directions folio closes the power source performance the influence to reduce to slightly. New power circuit analysis and new control technology. It may cause the power switch work at the zero potential or the zero electric current condition. Thus may the big enhancement operating frequency. Enhance the switching power supply working efficiency. Design the performance fine switching power supply.Efficient conversion of electrical power is being a primary concern to panies and to society as a whole. Switching power supplies offer not only higher efficiencies but also offer greater flexibility to the designer. Recent advances in semiconductor, magnetic and passive technologies make the switching power supply an ever more popular choice in the power conversion arena today.9中文開關(guān)電源技術(shù)在電力電子技術(shù)的應(yīng)用及各種電源系統(tǒng)中，開關(guān)電源技術(shù)均處于核心地位。 If in the electronic circuit the signal has the sudden change， the pulse like， Then belongs to the digital circuit. These two kind of electric circuits difference lies in the electric circuit neutron ponent working mode active status not to be dissimilar， latter daytoday work in switch condition, is when passes the time interval， First work in linear variation condition. The power switch in some design adopts a high frequency power conversion circuit using DCDC converter, which controls the energy flow by controlling the time ratio of switch and shutdown, and thus produces highquality adjustable DC output voltage. The switch has two major systems: the main control circuit and loop control circuit the main control circuit is the main AC transformer circuit which passes rectifier filter to the loading circuit, and the control loop circuit is a circuit which controls the work statue of the main control circuit according to the input and output conditions of PWM waveform generated by UC3843. The present day power supplies use a capacitive input filter when powered from the AC power line. A resulting shorting is that the AC line is rectified which results in high peak currents at the crests of the AC voltage as shown in Figure 13. These peak currents are typically three to five times higher than the average current drawn by the power supply. This causes excessive voltage drop in the wiring and imbalance problems in the three phase delivery system. Also the full energy potential of the AC line is not utilized.A popular method of acplishing this is by using a boost converter prior to the actual power supply. Boostmode supplies exhibit the largest input dynamic range of all the switching power supply topologies. Input voltages down to 30 volts can be boosted to 370 volts on its output (higher than the highest expected peak operating AC crest voltage). The boost power factor correction circuit can be seen in Figure 37 on page 37.The bulk input filter capacitor is now placed on the output of the boost converter. The input capacitor, just following the 50/60 Hz rectify bridge is now less than 1 181。s，Said regarding each kind of electric circuit and the system design. The simulation technology is useful. Specially, Such as the print making butut， electromagnetic patibility (EMC) the question as well as the power factor revises (PFC) and so on the question solution. It can not leave the simulation technology the knowledge. But regarding intellectualized switching power supply. Need to use the puter to control the time. The digitized technology could not leave. The electrical power system green has two meanings. First is the remarkable electricity saving， This meant generating capacity economy. But generates electricity is causes the environmental pollution the important reason. Therefore the electricity saving may reduce to the environment pollution. Next these power sources cannot (or are few) have the pollution to the electrical network. The international electrician mittee (IEC) has formulated a series of standards regarding， IEC917， IECl000 and so on. In fact，many powers electrons electricity saving equipment. Often it can turn to the electrical network source of pours into the serious higher harmonic current to the electrical network, causes the total output factor to drop, result of the electrical ne