TME carries a core for a flyback designed to supply 450V 100mA from a 10-14VDC supply. This sparked my curiosity. As flyback transformers are hard to come by unless you custom order.
So i got a bunch of these to play with: TI-EF25-1068 FERYSTER - Transformer: impulse | power supply; 45W; Works with: UC3843 | TME - Electronic components
However i was quickly stuck, because the data supplied is incomplete, however i emailed FERRYSTER and they promprly supplied me with all the data i need. So a shout out to them is in order!
Heres the data from their email to me:
Lprim 10.89 µH ±10%
Ratio 1:10
Ipeak 15.8 A
Isat >18 A
fosc 70 kHz (UC3843, DCM)
Rsc 0.075 Ω (Ipeak = 13.33 A), 0.068 Ω (14.7 A) 5 W
So it turns out these are optimized for 70Khz, which is convenient because it keeps the switching losses down. The 3843's output is not really suited to driving very large mosfets, so i will try a couple and see which one works best.
I want to try these with 68mOhm sense resistor value, and a number of switching Fet's i have on hand, more on this later.
Heres the circuit i came up with, its a test board, so i have not galvanic-ally insulated the output from input. Eventually i want to make a fixed 400V version that you can stack.
Are there Diyers with more experience in flyback design that want to lend me their 2 cents?
Eventually i also want to combine this flyback with a number of other flybacks to furnish all the power needed in a tube tester ! from a 12V bus (Cheap chinese SMPS anyone)
So i got a bunch of these to play with: TI-EF25-1068 FERYSTER - Transformer: impulse | power supply; 45W; Works with: UC3843 | TME - Electronic components
However i was quickly stuck, because the data supplied is incomplete, however i emailed FERRYSTER and they promprly supplied me with all the data i need. So a shout out to them is in order!
Heres the data from their email to me:
Lprim 10.89 µH ±10%
Ratio 1:10
Ipeak 15.8 A
Isat >18 A
fosc 70 kHz (UC3843, DCM)
Rsc 0.075 Ω (Ipeak = 13.33 A), 0.068 Ω (14.7 A) 5 W
So it turns out these are optimized for 70Khz, which is convenient because it keeps the switching losses down. The 3843's output is not really suited to driving very large mosfets, so i will try a couple and see which one works best.
I want to try these with 68mOhm sense resistor value, and a number of switching Fet's i have on hand, more on this later.
Heres the circuit i came up with, its a test board, so i have not galvanic-ally insulated the output from input. Eventually i want to make a fixed 400V version that you can stack.
Are there Diyers with more experience in flyback design that want to lend me their 2 cents?
Eventually i also want to combine this flyback with a number of other flybacks to furnish all the power needed in a tube tester ! from a 12V bus (Cheap chinese SMPS anyone)
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That sounds similar to this DC 12V-24V Step up to 200V-450V DC-DC High Voltage Boost Converter Power Module | eBay
although I don't know if it's flyback or not. It's not isolated from input to output, either but it's push pull.
The control chip has only Chinese on it, too. I have two of these collecting dust, I was thinking of
using one for a tube tester of sorts, too. Just rip out the 5k pot and use a panel mount version.
The switching frequency changes based on output voltage and loading, too. Oh and it HATES feeding a 4.5H choke input. I use one on a headphone amplifier. It's great when it doesn't oscillate.
although I don't know if it's flyback or not. It's not isolated from input to output, either but it's push pull.
The control chip has only Chinese on it, too. I have two of these collecting dust, I was thinking of
using one for a tube tester of sorts, too. Just rip out the 5k pot and use a panel mount version.
The switching frequency changes based on output voltage and loading, too. Oh and it HATES feeding a 4.5H choke input. I use one on a headphone amplifier. It's great when it doesn't oscillate.
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You might want to look at Ron Dekker's "Flyback Converters for Dummies" (I believe Ron is a physicist for Phillips). It's the basis for his work with nixies, and, of course, the uTracer
Flyback Converters for Dummies
Flyback Converters for Dummies