【正文】 h to fully offset the large account space to bring lowloss, no further increase when the meaning of duty, because the leakage inductance may even be too high against the peak voltage breakdown switch. Leakage inductance as large, may make the output ripple, and other electromagnetic indicators deteriorated. When the duty hours, the high RMS current through the switch, transformer primary current rms and lowered the converter efficiency, but can improve the working conditions of the output capacitor to reduce fever. How to determine the transformer reflected voltage (duty cycle) Some netizens said switching power supply feedback loop parameter settings, work status analysis. Since high school mathematics is rather poor, Automatic Control Theory, almost on the makeup, and for the door is still feeling fear, and now can not write a plete closedloop system transfer function, zero for the system, the concept of feeling pole vague, see Bode plot is only about to see is a divergence or convergence, so the feedback pensation cannot nonsense, but there are a number of remendations. If you have some mathematical skills, and then have some time to learn then the University of Textbooks, Principles of Automatic Control digest look carefully to find out, bined with practical switching power supply circuit, according to the work of state for analysis. Will be harvested, the Forum has a message, coach feedback loop to study the design, debugging, in which CMG good answer, I think we can reference. Then today, on the duty cycle of flyback power supply (I am concerned about the reflected voltage, consistent with the duty cycle), the duty cycle with the voltage selection switch is related to some early flyback switching power supply using a low pressure tube, such as 600V or 650V AC 220V input power as a switch, perhaps when the production process, high pressure tubes, easy to manufacture, or lowpressure pipes are more reasonable conduction losses and switching characteristics, as this line reflected voltage cannot be too high, otherwise the work order to switch the security context of loss of power absorbing circuit is quite impressive. Reflected voltage 600V tube proved not more than 100V, 650V tube reflected voltage not greater than 120V, the leakage inductance voltage spike when the tubes are clamped at 50V working margin. Now that the MOS raise the level of manufacturing process control, flyback power supplies are generally used 700V or 750V or 800900V the switch. Like this circuit, overvoltage capability against a number of switching transformer reflected voltage can be done a bit higher, the maximum reflected voltage in the 150V is appropriate, to obtain better overall performance. TOP PI39。s remendation for the 135V chipset with transient voltage suppression diode clamp. But his evaluation board generally reflected voltage to be lower than the value at around 110V. Both types have their advantages and disadvantages: Category: shortings against overvoltage, low duty cycle is small, a large pulse current transformer primary. Advantages: small transformer leakage inductance, electromagnetic radiation and low ripple index higher switch loss, the conversion efficiency is not necessarily lower than the second. The second category: a large number of shortings of power loss, a large number of transformer leakage inductance, the ripple worse. Advantages: Some strong against overvoltage, large duty cycle, lower transformer losses and efficiency higher. Reflected voltage flyback power supply and a determining factor Reflected voltage flyback power supply with a parameter related to that is the output voltage, output voltage, the lower the larger the transformer turns ratio, the greater the transformer leakage inductance, switch to withstand higher voltage breakdown switch is possible to absorb power consumption is higher, has the potential to permanently absorb the circuit power device failure (particularly with transient voltage suppression diode circuits). In the design of lowvoltage lowpower flyback power output optimization process must be handled with care, its approach has several: 1, using a large core of a power level lower leakage inductance, which can improve the lowvoltage flyback power conversion efficiency, reduce losses, reduce output ripple and improve multioutput power of the cross regulation in general is mon in household appliances with a switch power, such as CDROM drive, DVB settop boxes. 2, if the conditions were not increased core, can reduce the reflected voltage, reducing the duty cycle. Reduce the reflected voltage can reduce the leakage inductance but may reduce the power conversion efficiency, which is a contradiction between the two, must have an alternative process to find a suitable point, replace the transformer during the experiment can detect the transformer original side of the antipeak voltage, peak voltage to minimize the antipulse width, and magnitude of the work safety margin increase converter. Generally reflected voltage 110V when appropriate. 3, enhance the coupling, reducing losses, the introduction of new technologies, and the routing process, transformers to meet the security specifications will between the primary and secondary side to insulation measures, such as pad tape, plus side air insulation tape. These will affect the performance of transformer leakage inductance。 the reality can be used in production around the primary winding secondary wrapping method. Or subsystem with a triple insulated wire wound to remove the insulation between the initial levels, can enhance the coupling, and even use wide copper winding. 開關(guān)電源的設(shè)計開關(guān)電源分為兩個獨立形式的隔離和非孤立這里主要談?wù)勯_關(guān)電源拓撲結(jié)構(gòu)形式下，非指定的隔離電源。 供應(yīng)隔離電源按照不同的結(jié)構(gòu)形式可分為兩類：一激和反激。 回掃變壓器初級端意味著當(dāng)副邊導(dǎo)通截止，變壓器存儲。關(guān)閉的小學(xué)，中學(xué)側(cè)傳導(dǎo)，釋放的能量功率反激式多路給負載的工作狀態(tài)，一般常規(guī)，雙管是不常見的。遠期是指二次側(cè)主變壓器傳導(dǎo)而相應(yīng)的輸出電壓互感器誘導(dǎo)為負載，通過直接傳輸能量。按規(guī)格可分為常規(guī)推進，包括單管正激，雙管正激。半橋，全橋電路是向前電路激和反激電路具有電路設(shè)計他們自己的進程的特點，在達到