The common problems of switching power supply
How to calculate the power of the power of 1
The power supply is generally refers to the total power output, represented bythe letters P, unit W (Watt), the formula for calculating power to P=U*I power P=output voltage U*, output current of I, such as the power of a 12V1A, the total power voltage 12V* current 1A=12W.
2 power output voltage, output current than the rated current, can use normally?Will not damage the equipment?
In fact, the rated current equipment identification can be understood as the basicworking current, which is to make the normal operation of the equipment, power supply must be current supply current equal or greater. As long as the outputvoltage, output current power is greater, more power to represent power. Power of the bigger the better (of course, the greater the power the more expensive).For example, desktop computer ATX power supply 300W and 350W or 400W power points, they can be in the computer are used, the only difference the moreyou, if computer peripherals, such as mobile hard drives, external burner, high speed graphics, high frequency CPU, TV card and so on, the power only 300W isnot qualified, the consequences will be frequent crashes, restart, not normal use,so the supply of a large power is very necessary. From the principle of the analysis, the current demand is depending on the load (i.e. device), rather than depending on the power supply, but the maximum current power supply canprovide. If the horse to the power supply, the carriage to load, a strong horse and a little horse pulling a cart with the results, one can imagine. Have a friend take the power amplifier and the loudspeaker to compare, say for high power amplifierfor driving a small horn, a burned out, in fact, principle and power audio power amplifier is not the same, audio power amplifier amplification voltage, output is AC(AC) audio signal, audio signal voltage and increase as the volume increases,with a small power horn, do not burn just strange, so matching speaker andamplifier is very important. To sum up, the power supply voltage, current and the bigger the better, the more power of.OK. but remember not to select the currentthan the rated current of small, will be out of the question.
3 what are the functions of switching power supply protection?
Power supply in the high voltage environment, the lack of corresponding protection function of many hidden dangers, protect the most basic functionshould have: 1 input circuit protection, output short circuit protection, output short circuit protection, output over voltage protection, input voltage surge suppressionmutation protection etc....
Power 4 the same specifications, some Chinese cabbage price, why?
Internal power supply scheme and the use of materials determines the price,there are lots of power supply for second-hand recycling material production,stock return goods, defective goods, or shoddy work, as long as the power supply voltage output and other indicators on the matter, even the basicinductive filter circuit are omitted, or the use of the simple RCC scheme, i.e. atransistor as the switch tube, low efficiency, poor performance, high failure rate,but due to low cost, a lot of cheap power were adopted in this project done.Power slightly higher prices are in IC integration solution, cost is high, butperformance is good, high efficiency. This shop all power is the production ofpower management IC the world famous semiconductor manufacturers, such as Taiwan ang Pao, Fairchild.
5 safety certificates are those? What is the use?
Safety certificate by the importing country song, is an important index to measure the quality of power supply, the 8 country in the world developed has itscorresponding safety standards, products are exported to the country, must obtain the relevant safety certificates. As USA UL, Canada CUL, Japan PSE,Taiwan BSS, British LVD, German GS/TUV, European CE, Australia SAA,Chinese CCC certification etc.. To buy power certification, product labels are printed on LOGO certification mark corresponding, beside the logo can be foundin a set of code, can be related to the official website inquires the certificate of true and false. Or to the supplier to provide copies of product certification, can further verify the true and false.
6 need to add fuses at the input terminals of the module?
Answer: when a fault or abnormal circuit, with the current increasing, current andelevated may damage the circuit in some important devices or expensive devices,there may even cause a fire burned circuit. If the circuit correctly placed the fuse,the fuse will be in current, elevated to a certain height and a certain time, its fusecutting off the current, so as to protect the safe operation of the circuit. In accordance with international security standards, should be in the module (+)input fuse, and the board needs to be grounded.
7 what is the PFC?
Answer: PFC (Power Factor Correction) power factor correction, mainly used to characterize the electronic products to the utilization efficiency of electric energy.The power factor is high, the electricity utilization efficiency of energy is high. The switching power supply, the capacitor input filter, power factor is low, generally only about 0.65, greatly reduces the use of AC power rate, and this is accompanied by the non sinusoidal input current severe distortion and increase the pollution of the grid, in order to improve the power factor and the power factor correction circuit, PFC has two kinds, one a passive PFC (also known as passive PFC), is a kind of active PFC (also known as the active PFC).
8 what is the Y capacitor, can be substituted by other capacitance?
Answer: are respectively connected with the ceramic capacitor in the two inputline to ground, power conversion modules require online and chassis (earth) withbypass capacitor, to bypass common mode noise and limitation of the converter.When the converter in the AC rectified voltage, and bypass capacitor is damaged, it may cause serious leakage to electrical chassis, grounding fault and electric shock triggered. Therefore, the capacitor need to use a special kind ofapplication (called Y- capacitor). The capacitor
