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Julian
Apprentece
Malaysia
6 Posts |
 Posted - Jan 12 2012 : 11:44:36 PM
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Hi,i really need help on how to design a dual channel DC power supply that fulfills the following specifications :
1) Operation - User selection between independent adjustment for positive and negative output voltage, and series tracking mode (slave channel tracks the master channel)
2) Output voltage amplitude : 0-20V± 5%
3) Current limit : 0 - 1.5A± 10%
4) Powered Directly from main supply
5) Indications of power on, constant voltage and constant current mode
I really hope you guys will be able to help me and provide me with a schematic to achieve the above specifications..thanks in advance =) |
Edited by - Julian on Jan 12 2012 11:47:12 PM |
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Julian
Apprentece
Malaysia
6 Posts |
Posted - Jan 14 2012 : 02:51:06 AM
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| Can anyone please lend me a hand as it is a very important assignment i have to complete by the end of the month |
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pebe
Nobel Prize Winner
United Kingdom
1078 Posts |
Posted - Jan 14 2012 : 04:58:48 AM
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| You also posted the same request on another forum. Do you think it is reasonable to expect someone to do your class assignment for you, while you get the credit for it? |
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Julian
Apprentece
Malaysia
6 Posts |
Posted - Jan 14 2012 : 11:18:53 AM
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| I am sorry,i dont mean it that way..i just need a circuit as a reference because i have been searching for quite some time and i couldnt find the circuit i need..and my last resort is through forum because i guess i will be able to get a better chance of finding the circuit i am searching for..but if it offended you,i apologize.. |
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Julian
Apprentece
Malaysia
6 Posts |
Posted - Jan 14 2012 : 12:41:18 PM
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| btw..i found the circuit in this link http://www.aaroncake.net/circuits/supply3.asp and wanted to know how to improvised the circuit to give me an output voltage of 0-20v instead of just 0-15v..can u give me any suggestions?=) |
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pebe
Nobel Prize Winner
United Kingdom
1078 Posts |
Posted - Jan 14 2012 : 12:41:19 PM
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You have not offended me. Perhaps I misunderstood your question, but I thought you were asking for someone to provide you with a (complete?) circuit for a power supply, with specific requirements, for you to hand in for your assignment.
There are plenty of DC power supply circuits available on the net that could be fairly easily modified to meet your needs, but that would require some effort on the part of someone.
As this is for your assignment then it must be to help your tutor to assess if you are able to design one or modify an existing one. So the point I was making was:- Would not using someone else’s design make your assignment invalid?
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Julian
Apprentece
Malaysia
6 Posts |
Posted - Jan 14 2012 : 12:53:21 PM
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| As i am still new and not very strong in my electronics field,that is why i need some assistance from you to guide me in my assignment..sorry for asking for help in a wrong way which make you misunderstood..i dont need a complete circuit..i have found a circuit from this website as well which can be modified to suit my needs as you have said..i just need some help on modifying it..=) |
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audioguru
Nobel Prize Winner
Canada
4218 Posts |
Posted - Jan 14 2012 : 3:03:12 PM
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The dual power supply circuit you found on this website uses fairly low power adjustable voltage ICs.
Due to their low power then they get very hot and will shut down if their output current is 1.5A, their input voltage is 23V and their output voltage is less than 14V. Its voltages can be lower at 1.5A if you cool the ICs somehow (a huge heatsink and a fan?).
The current limiting is not adjustable, it is automatic. It will be typically 2.2A at high output voltages and a little over 1A at low voltages if it doesn't get too hot.
Its output voltages do not go down to 0V, its minimum output voltages are plus and minus 1.25V.
Its plus and minus output voltages are completely separate and do not track each other.
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Edited by - audioguru on Jan 14 2012 3:06:15 PM |
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pebe
Nobel Prize Winner
United Kingdom
1078 Posts |
Posted - Jan 15 2012 : 10:23:48 AM
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quote:
Originally posted by Julian
As i am still new and not very strong in my electronics field,that is why i need some assistance from you to guide me in my assignment..sorry for asking for help in a wrong way which make you misunderstood..i dont need a complete circuit..i have found a circuit from this website as well which can be modified to suit my needs as you have said..i just need some help on modifying it..=)
OK. Here is a link to the datsheet for an LM317. It is an adjustable voltage regulator and should provide the basis of what you need.
http://www.datasheetcatalog.org/datasheet/nationalsemiconductor/DS009063.PDF
There are application notes at the end for a variety of requirements, including more power. Note in particular, the circuit at the bottom of Page8.
For a supply giving positive and negative outputs you would need to use two identical circuits fed from separate supplies, with the +ve output of one connected to the -ve output of the other, as the common terminal.
To make the outputs track, you could use a dual pot for the two adjustment pot R8 on page8. Mount it as the main control for the +ve supply. If you then want to 'untrack' the two outputs you can switch the R8 control for the -ve supply over to its own R8 pot.
Best of luck |
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Julian
Apprentece
Malaysia
6 Posts |
Posted - Jan 15 2012 : 7:40:30 PM
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| Thanks a lot audioguru and pebe..you guys have certainly help me alot..appreciate it much..=) |
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Topic |
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Dual Channel DC power supply
