audioguru Posted November 16, 2011 Report Share Posted November 16, 2011 Hello.I'm new here.. Hello :DDo I really have to read through all the 85 pages to find out where I can get an updated BOM, schematic, and eagle drawings?Thanks.AndreasHi Andreas.It is too bad that the power supply kit posted in the original project was very poorly designed.We have made a few modifications over the years to fix it and I have posted the latest parts list and schematic millions of times.Here they are again: Quote Link to comment Share on other sites More sharing options...
benny8902 Posted November 24, 2011 Report Share Posted November 24, 2011 A 120VA transformer is slightly too small. Then when the project is supplying 3A continuously the transformer will be slightly warmer than its max allowed temperature.Inside a box it might get too hot.What if the transformer is bigger? Like 150VA. would that be a problem? Quote Link to comment Share on other sites More sharing options...
audioguru Posted November 24, 2011 Report Share Posted November 24, 2011 A 150VA transformer will be fine but is more expensive and is heavier. Quote Link to comment Share on other sites More sharing options...
zulcao Posted November 24, 2011 Report Share Posted November 24, 2011 Recently I got an 1000va :o by 24v, will work ? Quote Link to comment Share on other sites More sharing options...
audioguru Posted November 24, 2011 Report Share Posted November 24, 2011 With the 24V transformer, the max output voltage from this project is only about 25VDC.The 1000VA transformer will only partially be used since at 24V AC only 102VA is needed. It is expensive, big and heavy. Quote Link to comment Share on other sites More sharing options...
morpheous87 Posted November 27, 2011 Report Share Posted November 27, 2011 I want to ask, if the power supply gives 3A at 30V, can it give ~7A at 12V when charging 12V batteries ? Quote Link to comment Share on other sites More sharing options...
audioguru Posted November 27, 2011 Report Share Posted November 27, 2011 I want to ask, if the power supply gives 3A at 30V, can it give ~7A at 12V when charging 12V batteries ?Of course not! Its max output current is only 3A.The transformer is at its limit when the output current of the project is 3A.The output transistors and driver transistor (and maybe opamp U2) are also at their limit when the output is 3A.We have a thread about increasing the output current to 5A. A 3rd output transistor was added and a bigger transformer. Quote Link to comment Share on other sites More sharing options...
mas Posted November 28, 2011 Report Share Posted November 28, 2011 hi all;i maked this psu first version. it is worked very good but damaged. after i think make a new and more profesional. i look your updates and make a new pcb. i complete all but dont complete pcb routing. i want one side pcb. proteus autorouter draving 2 side. i dont want 2 side. i want only 1 side. maaybe need change component placing. can you complete this? i attached all files.. im using proteus 7.7 sp2. thanks. regards..0-30v_stablized_new_pcb.rar Quote Link to comment Share on other sites More sharing options...
garik111 Posted December 6, 2011 Report Share Posted December 6, 2011 Hi Andreas.It is too bad that the power supply kit posted in the original project was very poorly designed.We have made a few modifications over the years to fix it and I have posted the latest parts list and schematic millions of times.Here they are again:HiPlease suggest a heatsink and where I can buy transformer online? thanks Quote Link to comment Share on other sites More sharing options...
audioguru Posted December 6, 2011 Report Share Posted December 6, 2011 Since you do not show where you are then we cannot recommend parts.The max total dissipation from both output transistors is 117W. They should have their chips below their max temperature of 200 degrees C. If the ambient is 30 degrees C then the total allowed allowed temperature rise is 175 degrees C. 2N3055 transistors have a thermal resistance of 1.5 degrees C per Watt. An insulator with thermal compound is about 0.2 degrees so the total thermal resistance is 1.7 degrees C per Watt. The total thermal resistance must be at least 200 degrees/117W= 1.7 degrees C per Watt so the heatsink must be pretty big and a fan should be used.I am in Canada so I usually order online from Digikey and Newark. They both have very detailed catalogs online. If I order before 8:00PM then it is delivered to me the next morning. Quote Link to comment Share on other sites More sharing options...
Supernova Posted December 7, 2011 Report Share Posted December 7, 2011 I Have built the original circuit. It works perfectly, but now i want to modify it so it will give negative voltage. Can somebody help me do this because I don't even know if this is possible. Quote Link to comment Share on other sites More sharing options...
audioguru Posted December 7, 2011 Report Share Posted December 7, 2011 1) The original project has opamps rated for an absolute maximum supply of 36V operating at 40V.2) Its transformer, rectifier diodes, driver transistor, output transistor and many resistors get too hot and will probably fail soon.It cannot produce 30V at 3A.So we fixed it to work properly and be reliable.If you connect its + output to ground then its 0V output is a negative output voltage. Quote Link to comment Share on other sites More sharing options...
mas Posted December 8, 2011 Report Share Posted December 8, 2011 i have a question, can i use ILC7660 for negative opamp supply? i think use smps. transformers is very big,heavy,expensive,old vs.. thx.. Quote Link to comment Share on other sites More sharing options...
audioguru Posted December 8, 2011 Report Share Posted December 8, 2011 i have a question, can i use ILC7660 for negative opamp supply? i think use smps. transformers is very big,heavy,expensive,old vs.. The existing negative -1.3V supply for the opamp U3 is simple, cheap, supplies plenty of current and is fairly well regulated.The iCL7660 needs to have a resistor feeding a 9.1V zener diode to power it plus two capacitors. Its output current is low and is not regulated. Its output voltage must be reduced to -1.3V somehow but still allow lots of current.Why are you talking about a smps transformer? Quote Link to comment Share on other sites More sharing options...
mas Posted December 8, 2011 Report Share Posted December 8, 2011 this circuit working with old transformers. designed for transformers supply (sine wave) alternative voltage. will not work on dc voltage. because you can not converte positive dc to negative whit passive components for opamp supply.. Quote Link to comment Share on other sites More sharing options...
audioguru Posted December 8, 2011 Report Share Posted December 8, 2011 this circuit working with old transformers.Maybe.It uses ONE ordinary 28V or 30V, 50Hz or 60Hz power transformer.designed for transformers supply (sine wave) alternative voltage. will not work on dc voltage.Of course not, it uses an AC power transformer, not a 40V battery.because you can not converte positive dc to negative whit passive components for opamp supply..Why don't you power this project from a power transformer like everybody else? Quote Link to comment Share on other sites More sharing options...
mas Posted December 8, 2011 Report Share Posted December 8, 2011 Look please... Quote Link to comment Share on other sites More sharing options...
audioguru Posted December 8, 2011 Report Share Posted December 8, 2011 This project is powered from an AC transformer, not DC. Quote Link to comment Share on other sites More sharing options...
mas Posted December 8, 2011 Report Share Posted December 8, 2011 are you shure? :o what i say bro? this project powered ac. i want use smps (dc). i say will not work. because there are no sine wave for negative supply.. and i say ILC7660 usable for this.. okay?red marked area for negative supply.. Quote Link to comment Share on other sites More sharing options...
Hero999 Posted December 8, 2011 Report Share Posted December 8, 2011 I don't see why it wouldn't work.The ILC7660 would need a voltage regulator to reduce the supply voltage to below 10V.Look at the datasheet of the ILC7660 for its maximum output current rating.Calculate the negative supply current taken by U3 when the output voltage is 0V.If it's above the ILC7660's maximum rating it won't work.You could use the 555 timer and some diodes as an alternative which would work as long as the current through the 555's pin 3 is below 200mA. Quote Link to comment Share on other sites More sharing options...
ksenhuck Posted December 10, 2011 Report Share Posted December 10, 2011 Please guys, i'm completly lost... its my first time here....i just want to know, pleeeease ,which page the final circuit are? the pcb....i want to do the 0-25V 3A, so i can use an 25v-3A transformer, using the components of 30V-3a right? because i have already bought them, but i bought using the original circuit...pleease,i need the final pcb circuit and the list of the news components i am supposed to buy.....PLease guys, pleaseThanks a lot !! Quote Link to comment Share on other sites More sharing options...
audioguru Posted December 11, 2011 Report Share Posted December 11, 2011 A little 25V/3A transformer will overheat when it tries to supply more than 75VA.If the output voltage of the project is 25VDC at a current of 3A then the max (b]load(/b) power is 75VA.But the rectifier bridge uses an additional power of 6W max and the R7 current-sensing resistor uses 4.2W max. The electronic circuit also uses additional power. Then the transformer must supply more than 85.2VA which is higher than its max allowed rating of only 75VA.I posted the latest parts list and schematic a few hundred times here and I don't have time to post them again because your transformer is too small and maybe you can't find the modern opamps anyway. Quote Link to comment Share on other sites More sharing options...
ksenhuck Posted December 11, 2011 Report Share Posted December 11, 2011 i haven't bought the transformer .. i will check out again to find your schematic here, i just want to buy the right transformer....tks Quote Link to comment Share on other sites More sharing options...
ksenhuck Posted December 11, 2011 Report Share Posted December 11, 2011 Please audioguru, but this is the final circuit right?http://www.electronics-lab.com/forum/index.php?topic=19066.msg100521#msg100521tks Quote Link to comment Share on other sites More sharing options...
audioguru Posted December 11, 2011 Report Share Posted December 11, 2011 Please audioguru, but this is the final circuit right?http://www.electronics-lab.com/forum/index.php?topic=19066.msg100521#msg100521Yes you found the latest parts list and schematic. The transformer can be 28VAC/4.2A or 30VAC/4.2A. A higher current rating is fine. Quote Link to comment Share on other sites More sharing options...
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