autir Posted September 28, 2005 Report Posted September 28, 2005 Hello all :)I have decided that the new project I want to build ( a 1.2-30V, 3Amp variable PSU) should have a switching regulator IC instead of a linear one.After a search I have decided that National's LM2576T-ADJ is an IC well-suited for my needs.Does anyone have to propose a different solution? It must be in a package suitable for stripboard (TO-220 etc.), and a decent price (<5 Euros) would be a plus.Thank you. Quote
walid Posted September 29, 2005 Report Posted September 29, 2005 i think this is not the problem.....A switched mode power supply (SMP) uses a ferrite core transformer, how you will get it .If I in place of you i get this psu from a used computer monitor and modified it , or simply analyze it and understand the design. Quote
autir Posted September 29, 2005 Author Report Posted September 29, 2005 If you take a look at the datasheet, the adjustable output voltage version is what I have in mind. There is no ferrite core transformer in this circuit (or in any other circuits in this datasheet, if I'm not mistaken).Another problem:How could I provide the unregulated DC input voltage without use of any heavy power transformer? Quote
ante Posted September 29, 2005 Report Posted September 29, 2005 Hi autir,You could go for a primary switched PSU, no heavy transformer, small size, high efficiency, very small heatsink and heat loss!What more could you ask for? ;D Quote
Guest Alun Posted September 29, 2005 Report Posted September 29, 2005 Good idea Ante, but just make sure you add good enough protective devices like fuses and thermal cutouts safety 's sake, also ensure the transformer's primary and secondars are isolated by a good thick layer of insulation tape. Personally I wouldn't recommend building a mains primary switched PSU as it's not always easy to make it safe, under these circumstances I'd recommend an off the shelf solution. Quote
ante Posted September 30, 2005 Report Posted September 30, 2005 Hi Alun,The IC:s which are made for this purpose are equipped with several options for various kinds of protection. The standard way of doing this is by means of a galvanic insulated transformer…. as every transformer actually is made! Quote
autir Posted October 1, 2005 Author Report Posted October 1, 2005 You could go for a primary switched PSU, no heavy transformer, small size, high efficiency, very small heatsink and heat loss!Yes, that's what I want :DHave you got any tutorials/ docs in mind? What should I read to know how to start? Quote
ante Posted October 1, 2005 Report Posted October 1, 2005 Hi autir,I don’t have anything ready for you but take a look at : http://www.semiconductors.philips.com/acrobat_download/datasheets/TEA1552_2.pdfIt might give you something to start with.Similar ICs can be found with other manufacturers too. Quote
Shahriar Posted October 1, 2005 Report Posted October 1, 2005 The main problem in SMPS Designing is the transformer calculations.The best thing you can do, is copying from a TV schematic and buy the transformer. because finding the TV transformers is not very difficult. and the schematic is on the WEB ;DHTH - Shahriar Quote
ante Posted October 2, 2005 Report Posted October 2, 2005 It’s also possible to modify an old PC PSU to make it variable and change the voltage to any voltage you need. Quote
harrychoo Posted October 7, 2005 Report Posted October 7, 2005 I also having difficulty to understand the high freq transformer. I dunno how to read their specs and which spec i should use. Any help pls? ThanksWhat core of the transformer and what switching frequency normally being used? Quote
ante Posted October 7, 2005 Report Posted October 7, 2005 Hi Harry,This might be useful: http://www.electronics-lab.com/forum/index.php?topic=4523.0 Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.