To: Eva The symbol at pin 2 of IR2110 is mistakenly connected to the secondary side ground. Now the symbol is corrected.
I think the signal across the output current sense resistors will appear in correct polarity, so the connection of the transistor and the photo diode is required not to be changed.
I think the signal across the output current sense resistors will appear in correct polarity, so the connection of the transistor and the photo diode is required not to be changed.
xyz9915 said:
You are wrong little one 😉
When current flows from the SMPS into the battery the left side terminal of the sense resistors becomes negative with respect to the right side terminal. In other words, what you get is a negative current sense signal. This is very elementary (school) circuit analysis.
Remember that stable current limiting with a purely on-off signal coming from the secondary side requires slope compensation for duty cycles over 50%...
Dear Areza,
The Books you have prescribed for xyz9915 are required by me. Please let me know, how I can collect those Books ? I am in Dhaka and ready to pay the price of the Books. Please help me to collect those Books. I require those Books for enlarging my knowledge regarding smps. If you have the list of any other Books related to smps, please let me know.
The Books you have prescribed for xyz9915 are required by me. Please let me know, how I can collect those Books ? I am in Dhaka and ready to pay the price of the Books. Please help me to collect those Books. I require those Books for enlarging my knowledge regarding smps. If you have the list of any other Books related to smps, please let me know.
S.G. Mahbub @ i m not sure if you can pick them up from a book shop, better try in internet (googleing with torrent sites), there are many literature available in internet , specially appnote from ir, st, texas ins, motorola etc on various issues, at this moment the soft and literature i have is about 5GB and its getting bigger, yet its a tiny part of the whole smps game, so you understand the limitation of human being to accumulate all the knowledge of just one object,
After receiving constructive criticism in the design, I have changed the design by using UC3842 Current-Mode PWM Controller chip. The data sheet is available with various manufacturer, while one page from http://onsemi.com is shown in the attachment. The schematic is then modified by me to fulfill my requirements. (Both schematic original & modified are in the same attachment), so, please point out if any further change is required.
(Both schematic original & modified are in the same attachment), so, please point out if any further change is required.
(Both schematic original & modified are in the same attachment), so, please point out if any further change is required.
Thank you Areza for your advice. Searching and collecting Books from abroad is alright. I thought, I can procure those Books in Dhaka with your help and my money.
I want to learn more, because I find that the informations provided by different Companies are not full proof all the time and the knowledge I gained during my Engineering Course are not practical enough. While indulging in smps, I find that lot of ingenuity based on solid foundation of one's own mental faculty is required.
Thanks again.
I want to learn more, because I find that the informations provided by different Companies are not full proof all the time and the knowledge I gained during my Engineering Course are not practical enough. While indulging in smps, I find that lot of ingenuity based on solid foundation of one's own mental faculty is required.
Thanks again.
Hi xyz9915
I wouldn't probably say anything, but you just can't change few parts and hope to get what you want.If that was so, I would already build say 2kw one, others, well 20kw and more coz some really need them. Now go back to original design that you posted last. See and calculate that original output power was ~27w, and you wanna get 320w. It will just not work for you.
Modify some old AT or ATX psu first!! And check it good, you will see that they are half-bridges, not flybacks!
I wouldn't probably say anything, but you just can't change few parts and hope to get what you want.If that was so, I would already build say 2kw one, others, well 20kw and more coz some really need them. Now go back to original design that you posted last. See and calculate that original output power was ~27w, and you wanna get 320w. It will just not work for you.
Modify some old AT or ATX psu first!! And check it good, you will see that they are half-bridges, not flybacks!
From my experience, all the new designs I have encountered are flyback. The older ones were half bridges, however.luka said:
As i understand, he wants something like 12V 12A which are 144W. Easy for HB, FWD. Full bridge is an overkill. Very difficult for push-pull. A flyback is OK but the power level is a bit high for good flyback design.
Are you sure? Pretty new, 350w was half bridge still... How powerful were they? Big main trafo?star882 said:
A 430w (ThermalTake), a 350w (Antec), and some 250w and 200w (Dells) all use a flyback design. The transformers are indeed a good amount larger than the ones in the half bridges of similar power rating. They're all based on the "Channel Well" design.luka said:
I think one of the reasons they went that way was the difficulty of designing a cheap, efficient drive circuit for half bridges. A flyback circuit is simply much easier to design a driver for as there's only one switching transistor. Also, the controllers are becoming more integrated as power supplies become more sophisticated for efficiency reasons. It is common for one chip to handle the main converter was well as the preregulator. (The standby supply is separate as it also supplies the power for the main controller on the primary side.) A much simpler controller on the secondary side handles voltage feedback (though optoisolators to the primary controller) and fault detection.
I don't think they are forward converters since there is no "anti flyback" diode and winding on the primary side. It might be a flyback-forward design, but I'll have to trace the rectifier circuits again to check.switchmodepower said:
BTW, one of the Dells actually ran the fan from a separate small rectifier without any filtering. The idea is that at low load, the power supply will be working at low duty cycle so the fan will turn slowly. Increase the load and the fan speeds up. Of course, I rewired the fan to the regular 12v output so it will run at full speed all the time.
Actually maybe they are flybacks since the only advantage over the forwards would be no output choke for the multiple windings.
Eva, I am working on a full bridge circuit to convert rectified 220v dc to 220v ac. I have tried using IR2110, but the circuit failed to deliver any output. So, I request you to provide me an appropriate circuit, if you have no objection.
switchmodepower said:
You are forgetting the high capacitor ripple currents in a flyback. For a 20A output the capacitor ripple current will also be something like 20A... I've seen a couple of single-ended forward PC-supplies but only one 100W or so that was flyback. It is possible to do a forward converter without reset winding using the same kind of snubber as is usually used in flybacks. It gives a bit lower efficiency but not much if ,magnetizing inductance of the transformer is kept high.
It should be easy to see if it is a forward - if it has an output inductor for the main outputs it is, if it hasn't - flyback. But that seems pretty insane at 350W...
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