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Fiber Optic Media Coverters Fixed Switch

Edit:Aifon Technology Co.,Ltd      Date:Jun 05, 2017

Fiber Optic Media Coverters The difference between Open-loop and closed loop: The previous Open-loop simulation uses the output voltage obtained by the fixed switching frequency and duty ratio. The closed loop is sampled by the output voltage and then compared with the reference voltage. Fiber Optic Media Coverters After the error is enlarged and compared with the triangular wave to control the duty cycle size, thus controlling the duty cycle of the driving signal, the control MOSFET opening off time to achieve closed-loop control output voltage stability.

The Resistance R2 and R3 are sampled from the output voltage, and the error variance is Vref2.5v with the reference voltage and the OP1 bit error amplifier. Fiber Optic Media Coverters RC1 for RC compensation. The output voltage Vcmp of the error amplifier is compared with the Vramp triangular wave. COMP1 is a comparator. The output is a variable duty-ratio PWM control signal control M1 switch. The above can realize the closed loop simulation of the output voltage.

Positive Converter magnetic element in addition to the transformer, there is also an inductor, that is, choke. The general data are from the beginning of the transformer, but I think should start from the inductor to calculate better, so clear, thinking can be clearer. Because the positive converter originated from Buck converter, and Buck converter, the power of the heart is the energy storage inductance, Fiber Optic Media Coverters therefore, positive converter power heart is a choke, not transformers, transformers only responsible for variable voltage, and no other function, power transmission is inductance.

First of all, the filter inductor is studied. In a cycle, when the switch tube is opened, the filter inductance is added with a voltage, the current is not a mutation, but the linear rise, there are formula Ivi Ton L, these items respectively indicate the increment of inductance current, Fiber Optic Media Coverters input voltage, opening time, inductance quantity. And this voltage is the transformer by the side of the release. When the switch tube is off, inductor with a constant voltage discharge, its current will be linear descent, also abide by this formula, that is, Ivo, a cycle, discharge current equals charging current, so on two equal, then use D instead of Toff de instead of ton, Fiber Optic Media Coverters so from the upper two-way to get Vo vid.

Positive transformer and flyback transformer is a big difference is that the positive transformer is not open air gap, the demand for its inductance as large as possible. Positive transformer original side also has current, but this current is not its own through the input voltage storage, but from the side inductance induction over, know this point, the positive transformer is good design.


The first step is to determine the number of original edges. Of course, first of all to choose a cores. Set the original edge input minimum voltage is VS, Fiber Optic Media Coverters lead time with Ton said, but also to set a magnetic core amplitude, generally I take 0.2 to 0.25T, because the positive transformer is not required DC components, so compared to flyback this value can be larger, the original side turn number Np vs, wherein AE is the core cross-sectional area.


The second step, determine the number of vice-side turns, because in the opening of the switch tube, the side to V voltage discharge, and this v value, Fiber Optic Media Coverters the above has been set in the switch tube duty ratio of the time to determine, so the vice side turns number NSZHNP


The third step, draw the original edge current waveform, calculate the effect of the original edge current waveform, so as to determine the line diameter. As shown in the following figure, the waveform is the part of the inductance current waveform switch tube, because the current waveform is induced by the side edge.


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