Hi,
A couple of years ago I purchased a job lot of small flyback transformers, originally designed for off-line low power switched mode power supplys, maximum 22W (according to the spec sheet).
Primary is 65-280VAC, secondaries are 5V@3.2A or 12v@1.8A max.
Now, for a while I've been trying to design a relatively simple but versatile 300V supply for capacitor charging and xenon strobes - that is, can run off a wide supply voltage, and gives the user a selectable peak current draw . I decided on flyback topology as the output voltage has such a wide range (0-300v as the cap charges), plus its 'relatively' simple to control using either IC's specific for the job, or even a boost converter IC. After spending some timegetting to know PSPICE, I have simulated some pretty cool peak-current-flyback circuits, which I am confident will be a good start.
Now, the tricky part is the coupled inductor/transformer.
With an input voltage of 5-12V, I'm tihnking a turns ratio of 1:12- 1:15 for a max output of 300V. I'm hesitant to go over this, because my design relies on the reflected voltage on the primary to measure the peak voltage on the secondary - a higher ratio means this reflected voltage will be smaller.
My question is, would it be possible to use an off-line flyback in reverse? I realise its not as simple as using a forward transformer in reverse, since it is down to inductances rather than simply turn ratio. Has anyone done this without having to completely rewind it?
Blueteeth
A couple of years ago I purchased a job lot of small flyback transformers, originally designed for off-line low power switched mode power supplys, maximum 22W (according to the spec sheet).
Primary is 65-280VAC, secondaries are 5V@3.2A or 12v@1.8A max.
Now, for a while I've been trying to design a relatively simple but versatile 300V supply for capacitor charging and xenon strobes - that is, can run off a wide supply voltage, and gives the user a selectable peak current draw . I decided on flyback topology as the output voltage has such a wide range (0-300v as the cap charges), plus its 'relatively' simple to control using either IC's specific for the job, or even a boost converter IC. After spending some timegetting to know PSPICE, I have simulated some pretty cool peak-current-flyback circuits, which I am confident will be a good start.
Now, the tricky part is the coupled inductor/transformer.
With an input voltage of 5-12V, I'm tihnking a turns ratio of 1:12- 1:15 for a max output of 300V. I'm hesitant to go over this, because my design relies on the reflected voltage on the primary to measure the peak voltage on the secondary - a higher ratio means this reflected voltage will be smaller.
My question is, would it be possible to use an off-line flyback in reverse? I realise its not as simple as using a forward transformer in reverse, since it is down to inductances rather than simply turn ratio. Has anyone done this without having to completely rewind it?
Blueteeth