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bibo1978
Joined: 01 May 2004
Posts: 229
Helped: 6
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 21 Jun 2004 15:48 Switched mode power supply |
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| I need to make two switched mode power supplies with proper bypassing for rf-range the supply should work at 3.3 V with a power of 2.5 W, the design should be as small as possible can anyone supply me with resources
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uladz55
Joined: 11 Mar 2004
Posts: 161
Helped: 6
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22 Jun 2004 5:07 Re: Switched mode power supply |
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May be MAXIM Regulator series for RF applications can help you,
for example
http://para.maxim-ic.com/part_search.asp?TREE=PowerSupplies&SRCH=max1820
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metal
Joined: 21 Dec 2004
Posts: 369
Helped: 13
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andy1
Joined: 24 Jul 2004
Posts: 126
Helped: 2
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29 Dec 2004 18:46 Re: Switched mode power supply |
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If you're concerned about noise but want efficiency then you can use a switching power supply to step down to about 5V then use a LDO linear power supply to step down to 3.3V.
Try quality caps to further suppress ripple noise at output.
Also use a ferrite beat from 5V to 3.3V stage.
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29 Dec 2004 18:46 Ads |
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metal
Joined: 21 Dec 2004
Posts: 369
Helped: 13
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02 Jan 2005 12:06 Re: Switched mode power supply |
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Hello
Another idea, you can use low voltage logic inverters the work from 3.3 volt and use as many gates as you want to make the switching power supply to obtain 2.5 watt.
Regards
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kiger
Joined: 30 Mar 2003
Posts: 14
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05 Jan 2005 4:29 Switched mode power supply |
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A book about Switched Mode Power Supply
h**p://www.edaboard.com/viewtopic.php?t=50703&highlight=smps
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metal
Joined: 21 Dec 2004
Posts: 369
Helped: 13
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06 Jan 2005 23:57 Re: Switched mode power supply |
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Hello
Try Texas Instruments power management products, anr plug-in power modules, you may find something good for what you want.
Regards
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tocal09
Joined: 12 Jan 2005
Posts: 62
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19 Jan 2005 14:10 Re: Switched mode power supply |
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I want to make a DC_DC converter too. I've readn about the TL494 , and I want do it but don't know how to calculate the transform . Can I use the transform in AT/ATX power supply and how to use it (calculate).Could you help me ?
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tocal09
Joined: 12 Jan 2005
Posts: 62
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19 Jan 2005 14:19 Re: Switched mode power supply |
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| Can I use the MOSFET ex :IRF540,IRF640,IRFZ44.... for this circuit ?(I want to increase it's power)
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VVV
Joined: 26 Nov 2004
Posts: 1583
Helped: 290
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19 Jan 2005 18:39 Re: Switched mode power supply |
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If the DC-DC converter does not need isolation, then you do not need a transformer, you can just build a buck regulator. There are plenty of buck regulators and controllers out there for this job.
I would not use the TL494 for a DC-DC. There are many other IC's that can do the job. Is isolation really necessary? If so, I can tell you how to calculate the transformer, but if at all possible try to avoid using one.
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tocal09
Joined: 12 Jan 2005
Posts: 62
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26 Jan 2005 13:57 Re: Switched mode power supply |
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In my country , it's hard to find more IC for this job (maybe I don't know) .Could you post here several name of them or link for me . Before I always think transform is good for DC to DC converter . Now I want to make the 12VDC to 24VDC and more than 4A .
Added after 3 hours 47 minutes:
If isolation not necessary .Which IC you usually use for this work
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VVV
Joined: 26 Nov 2004
Posts: 1583
Helped: 290
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27 Jan 2005 18:24 Re: Switched mode power supply |
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A very popular chip is the UC3843. The only drawback is that you most likely need a current tranformer, since the current sense voltage is relatively high, about 0.7V.
A chip with much lower sense voltage (0.1V) is the MAX668, boost converter from Maxim. I cannot say for sure if you can use it for 100W output, but you can always use a MOSFET driver. Nice part. I used it in several designs.
I hope I understood correctly that you wanted a DC-DC 12V in, 24V out. If you can provide just a few more details, I may be able to suggest something.
Also check out Linear Technology, Texas Instruments, National, Micrel and ST websites.
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tocal09
Joined: 12 Jan 2005
Posts: 62
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29 Jan 2005 10:51 Re: Switched mode power supply |
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| I'm making an mini machine .It's motor using 24VDC but we want use 1 (not 2) 12V4Ah battery because several reason .So we must have a 12VDC to 24 VDC converter .Here it requirement have out put at 24VDC and current out more than 3Amp
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VVV
Joined: 26 Nov 2004
Posts: 1583
Helped: 290
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29 Jan 2005 22:28 Re: Switched mode power supply |
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The MAX668 I suggested in a previous post should do it. Take a look at this:
www.maxim-ic.com/appnotes.cfm/appnote_number/910
If you need help with the inductor, let me know.
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tocal09
Joined: 12 Jan 2005
Posts: 62
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03 Feb 2005 8:26 Re: Switched mode power supply |
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| I'm ordering sample this from Maxim . If they come I'll ask you about inductor
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tocal09
Joined: 12 Jan 2005
Posts: 62
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24 Mar 2005 8:32 Re: Switched mode power supply |
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| Well,now I've got 2 max668.It rather small.
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pccegoa
Joined: 10 Apr 2006
Posts: 1
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10 Apr 2006 11:46 Switched mode power supply |
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| how do u use a irf ina circuit?????i want d biasing circiut for it.......
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