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Flyback Isolated Feedback

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15 Threads found on Flyback Isolated Feedback
Hello, i have recently designed a 7V to 200V DC-DC SMPS converter, using LT3757. The output current is in the 1-10mA range. I use a DA2032 from coilcraft with a 1:10 ratio. At steady state, i get peak currents of 1.5A at the primary. My controller supports only non-isolated flyback, due to the nature of the resistive divider from the output. I a
Hello all. I am working on a microcontroller based flyback converter. Since the flyback converter is an isolated DC-DC Converter, it is using an opto-isolator as a feedback element. Attached with this post is an image from a Texas Instruments Application Report of a TL494 based multiple output flyback (...)
Hello everyone! I am at prototype stage of making power supply like in title. The problem is my output is 10 times smaller than it was expected to be - i have 0,33 V instead of 3,3 V . I have no clue what could be wrong, circut on the board is ok, transformer also seems to be ok. Any suggestions will be checked instantly, thanks for any response
Hello, I am doing a 45W, DCM flyback (isolated) with 90-265VAC mains input. (Vout = 25V) The feedback is optocoupler based. When the electrolytic capacitors in the output get older and have a greater ESR, this will reduce the ESR zero in frequency. Will this mean that its likely to go unstable? Or will the reducing ESR zero (...)
Hello Page 6-2 of the following has a schematic of a flyback with a UC3901 isolated feedback generator Page 6-12 onwards explains the feedback loop. ...however, i am unable to write down the poles and zeros of the error amplifier transfer i am confused by the UC3901 and
Hi Prashanttiyagi As Bradtherad said one of the best solutions is a buck converter . but there is another way available too . i think with this low voltage , you don't need any isolation , so a simple flyback converter , with non isolated feedback ( with two resistors and a common ground ) can be ok too . But another thing , if you use a (...)
hii, In one of my flyback smps configuration working in non-isolated topology iam using current mirror based feedback instead of using optoco upler. The circuit works fine , but under higher main voltage i.e. 40% of 230V. The trannsistor in current mirror Q2, Q3 and Q1 gets shorted which inturns destroys switcher IC. Drain and source (...)
hii, what would be the circuit and design parameters i need to consider if i have to design a feedback circuit using TL431 for a non isolated smps. Even though i am using a transformer. But the secondary and primary ground are common. 2. In a multiple output flyback smps, reflected voltage is secondary voltage multiplied by turns (...)
Most commercial DC/DC modules are using flyback for multiple output modules. It's the only way to get off without secondary regulation or other multi stage designs. Input ripple can be LC-filtered. Inter-windings capacitance and respective injected interference current are a more serious problem in isolated DC/DC, I think.
Hello, I do isolated , offline flyback. TL431/Opto-coupler feedback. The problem is, the 1K resistor that's across the opto-diode to provide the TL431 bias current, places a voltage across the opto-diode of 1 Volt.... ...this in turn makes it conduct current, which is a big big problem on maximum load, because if 180uA is drawn (...)
Hi, I'm building a voltage feedback flyback converter to turn a 12v input into a 24v output at 1Amp. I've successfully simulated and built this circuit on breadboard without isolation. Now I'm adding isolation. A tranformer in the forward path and an opto-coupler in the feedback path, but I'm having major headaches with the opto-coupler. (...)
I have a simple flyback circuit why CD4069? because I had 25 of them. input is 10-12V, output 250V. not exactly isolated, as I connect the grounds for 12V and 250V thru a resistor. The feedback is using a voltage
auxiliary coil feedback control is always going to be rough and ready especially with offline flybacks ...but you only do low voltage. so you need to increase coupling between aux and secondary by winding them with each other, say. or you wind secondary in two sections and "sandwich" the aux coil between the two sec halves this will also i
Hi, I would like to have you opinion on this simple topology (see the attached image) to get an isolated feedback from the secondary of a flyback. Does this circuit work? I think the CTR of the opto has a big influence on the regulated supply. Is it true? Could you suggest me the simple way to get an isolated (...)
Hello, On page 12, 13 and 14 of AN1059 application note they do the feedback compensation for the L6561 flyback power factor corrector circuit. However, considering the equation at the bottom of page 13 (H(s)), or any other transfer functions listed, -None of them include the effect of the opto-coupler pole. ****AN1059 flyback (...)