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Re: Ask Mel Berman, from TDK-Lambda a question
curtisJun 4, 2009 7:56 PM (in response to nlarson)
thanks,wish more people can get support from Mel Berman .
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Re: Ask Mel Berman, from TDK-Lambda a question
ghouse Mar 31, 2010 5:03 AM (in response to nlarson)Q for Mel Berman, I am looking for a good PWM control IC for current mode,
(pulse by pulse current sensing) for push-pull,
with LEB and slope compensation. Could you please suggest some IC's and the manaufacturuers?
I have seen the Texas UC3825ANUC3825AN and UCC38084 (this doesn't
have LEB) and Linear Tech LTC3721-1 and Nat Semi LM25037. Thanks. Ashley.-
Re: Ask Mel Berman, from TDK-Lambda a question
mberman Mar 31, 2010 11:16 AM (in response to ghouse)Hi Ashley,
I suggest you contact Texas Instruments.
TI has a number of control ICs that may fit your need and their app guys are very good.
All the Best, Mel
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Re: Ask Mel Berman, from TDK-Lambda a question
ghouse Apr 2, 2010 12:33 AM (in response to mberman)Thanks for the info, I will contact Texas. Do you know if there's a website that lists which ICs are suitable for all the different topologies i.e. buck boost push pull etc.?
Ashley
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Re: Ask Mel Berman, from TDK-Lambda a question
mberman Apr 2, 2010 10:25 AM (in response to ghouse)Hi Ashley,
This TI website may be helpful, if not, search a bit more via Google:
http://focus.ti.com/docs/toolsw/folders/print/pmp156.html
All the Best, Mel
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Re: Ask Mel Berman, from TDK-Lambda a question
Rahul PV Oct 7, 2010 2:02 AM (in response to mberman)Hi Berman,
What are the importance and difference of digital and analog ground in a circuit?
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Re: Ask Mel Berman, from TDK-Lambda a question
mberman Oct 7, 2010 10:47 AM (in response to Rahul PV)Hi Rahul,
Analog circuits tend to be more sensitive to incorrect grounding methods. However, in the design of both digital or analog circuits, care must be taken to prevent unwanted circulation currents in the ground connections, which are sometimes referred to as "ground loops". This is a very complex subject, with many differing opinions, and so I suggest you do some research on it if you want to know more.
Regards,
Mel
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Re: Ask Mel Berman, from TDK-Lambda a question
jim3363 May 26, 2010 11:25 AM (in response to nlarson)I run a KBCC-255 Penta Power control for a 5hp motor. I keep blowing the power bridge. I know it's because of not having the CL & IR pots not set right. Is it because of having the CL set too high or too low?-
Re: Ask Mel Berman, from TDK-Lambda a question
mberman May 26, 2010 12:03 PM (in response to jim3363)Hello Jimmie,
Sorry, but I am not involved in "motor drives".
May I suggest you contact the manufacturer for assistence if you have not done so already.
I did find a web link that lists the Manual for your device.
Here it is: http://www.kbelectronics.com/catalog_chassis.htm
Best regards,
Mel
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Re: Ask Mel Berman, from TDK-Lambda a question
yrault May 31, 2010 4:10 AM (in response to nlarson)Hi,
I'm searching a charger component for a battery pack of 2 cell LiFePO4 (7,2V or 7,4V) from USB supply.
Havee you got reference of a charger component who integer step up regulator, or a step up regulator who can start in short circuit?
Thanks
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Re: Ask Mel Berman, from TDK-Lambda a question
mberman Jun 1, 2010 10:23 AM (in response to yrault)Hello Yann,
There are many USB chargers and regulator chips on the market today.
I suggest you do some research via Google or other search engines.
Kind regards,
Mel
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Re: Ask Mel Berman, from TDK-Lambda a question
Nortski Jun 3, 2010 5:21 PM (in response to mberman)I'm sure that TI, Linear, National & Analog Devices have something like that. The Analog ADP1111 has adjustable current limit, but might not have the desired output voltage.
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Re: Ask Mel Berman, from TDK-Lambda a question
seba Jul 6, 2010 1:13 AM (in response to nlarson)Hello,
I want to cerate DC-DC converter from 12VDC to -300VDC. Output voltage must be stable as possibile. Iout < 3mA. Uout will be reference votage for measurement system with 16bit ADC. I try to do it with use flyback regulator with reversing amplifier on feedback. Is this a good way?
I will be grateful for any help.
Best regards
S.
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Re: Ask Mel Berman, from TDK-Lambda a question
mberman Jul 6, 2010 11:55 AM (in response to seba)Hello S.T.
Our company provides assistance in the "Applications" of AC-DC power supplies and DC-DC converters. We do not provide designs for these units.
However, I found a web site that may apply to your needs as follows: http://www.eleccircuit.com/dc-power-supply-300v-from-battery-12v/
A word of caution: This involves very high voltages that are dangerous and can be fatal. We cannot assume responsibility for these designs nor their safety. It would be best for you to purchase a ready made commercial unit. Many of these can be found on the internet.
Best regards,
Mel
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Re: Ask Mel Berman, from TDK-Lambda a question
seba Jul 15, 2010 3:47 PM (in response to nlarson)Thank you, but your suggested solution is not very stable without feedback. And I want to use this converter as a source of reference voltage -300V (minus 300V).
Anyway thank You.
Best regards.
S.
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Re: Ask Mel Berman, from TDK-Lambda a question
drolsen Aug 9, 2010 4:22 PM (in response to nlarson)Hi Mel,
Have a power supply question here.
A few years back there was a AC/DC 12 volt power supply listed on this site. It was one that I used, made a board for for and has worked very well. I found a site that has a full description of the schematic.
http://www.circuit-projects.com/battery/car-charger-for-12v-batteries.html
I recently had a charger/voltage regulator go out on a lawn tractor (dealer say's he'll be happy to replace for $80). The tractor has a alternator output of 28V, 10A I am trying to make this circuit work for the tractor, however the input voltage to the bridge rectifier is so variable (based on engine RPM's). I understand this circuit. I would like to utilize the 10A if headlights, clutches, etc. are engaged, I may need the output. Modifications that were made to my original design was to put a 2N6397TG2N6397TG in the place of the Q1. I realize it is a comparator circuit of sorts, but I am unsure as to regulating the voltage in front of the Q1 without the use of a 7812 (too low of a rating), if I could find a 13.5V 10A voltage reg, I had might as well go buy the part from the dealer (cost factor). Any suggestions?
Ps. I would like to keep the LED functionalty
Dave
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Re: Ask Mel Berman, from TDK-Lambda a question
mberman Oct 8, 2010 5:06 PM (in response to drolsen)Hi Dave,
I am not an expert in the area of battery chargers. And, I'm not sure from your description exactly what you asking.
For me, if I had a battery charger or voltage regulator go out on my car, I would buy a replacement.
Since your lawn tractor had a charger/voltage regulator go out, my advice is to buy a replacement unit and install it yourself.
These units are designed for the variables of engine speed, temperature, shock & vibration, water/moisture, cold, etc.
I know this is not the techie answer you may have expected, but it's the most practical one.
And, I believe you will save money in the long run by just replacing the defective unit.
Regards,
Mel
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Re: Ask Mel Berman, from TDK-Lambda a question
coolguy Sep 19, 2010 11:42 PM (in response to nlarson)hi, i have a question, i have a car stereo power amplifier that drains approx 120amps from 12volts. it drains my car battery in a few minutes. i want to run a 240v to 12v power supply capable of keeping it going but the biggest psu i've found is only 25amp output. can i get 5 psu and join them together on the 12v dc side to output over 120amp? think is that im worried because i don't want any feedback into the psus or oscillation at the frequencys it runs at.-
Re: Ask Mel Berman, from TDK-Lambda a question
mberman Jun 10, 2015 2:32 AM (in response to coolguy)Hi Ben,
It seems you have a huge amplifier that draws 1440 watts of power. I assume that for your 240V input application that your amplifier will be stationary and the power supply will be plugged into an AC outlet. Is this correct? If so, there are a number of AC-DC power supplies that you can use, including the following models from TDK-Lambda:
1 HWS1500-12HWS1500-12 provides a DC output of up to 12V@125V. http://www.us.tdk-lambda.com/lp/products/hws-series.htm
2 SWS1000L-12SWS1000L-12 provides a DC output of up to 12V@88A and two units can be connected in parallel (with the current-share feature) to provide up to 12V@176V. http://www.us.tdk-lambda.com/lp/products/sws-series.htm
I hope this answers your question.
Regards,
Mel
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Re: Ask Mel Berman, from TDK-Lambda a question
abdulhaseebop Oct 7, 2010 12:23 PM (in response to nlarson)Q for Mel Berman: As a part of my project , a home automation product - a smart switch which replaces the existing mechanical switch , i want to make a power supply from mains for the internal circuitry operation. The only two terminals available for me are one is the Line and the other is one end of the load .During Swicth Off position , there will be 230v ac available across the switch which i will rectify to get the required dc. During switch ON position I will have current ,which i have to convert to voltage abd get the supply . As the final size of the product is critical , am facing difficulties to implement these two especially the CT portion.
Thanks
abdul haseeb
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Re: Ask Mel Berman, from TDK-Lambda a question
mberman Oct 7, 2010 12:59 PM (in response to abdulhaseebop)Hello Abdul,
Your question is not clear to me. If you can send me a schematic drawing and more information I may be able to assist you.
Regards,
Mel
E-Mail mel.berman@us.tdk-lambda.com
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Re: Ask Mel Berman, from TDK-Lambda a question
Razputin Oct 24, 2010 2:42 PM (in response to nlarson)Question to Mr Berman Is it somehow possible to construct a DC-DC converter that can take an input voltage from 0.2-0.6V and up it to 5v? What Im thinking of here is a single PV-cell that can deliver 4W... The converter doesent have to start from the input, because I will have a battery backup to run a MC. Best Regards Rasmu Hildonen
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Re: Ask Mel Berman, from TDK-Lambda a question
mberman Oct 25, 2010 1:38 PM (in response to Razputin)Hi Rasmu,
As you know, most PV-cell applications involve multicells in series and parallel combinations. This is a tough application because of the very low input voltage. However, you say that for start-up the voltage does not have to be as low as 0.2 to 0.6V. What you need a very low voltage step-up DC-DC converter. I found a possible solution for you at this web address: www.national.com/ds/LM/LM2621.pdf
This device can operate with an input voltage as low as 0.3V and can provide your 5V output.
Other devices similar to this one may be found via an internet search.
In addition, I found a DIY design at this website:
http://www.discovercircuits.com/H-Corner/05-6-con.htm that perhaps can be modified to meet your needs.
Hope this helps.
Best regards,
Mel Berman
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Re: Ask Mel Berman, from TDK-Lambda a question
lowmy2005 Nov 23, 2010 12:33 AM (in response to nlarson)Hi Mel,
I would like to step down the power supply from 48Vdc to 28Vdc and the typical current is 12.5A. Do you have any solution?
Thanks.
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Re: Ask Mel Berman, from TDK-Lambda a question
mberman Jan 5, 2011 1:32 PM (in response to lowmy2005)Hello lowmy2005,
Yes we do have a solution for your DC-DC conversions needs. Our model PAF500F48-28 operates with a 48Vdc input and provides a regulated 28Vdc output at up to 18 Amps. Here is a web link to the datasheet for this product:
http://www.us.tdk-lambda.com/lp/products/paf-series.htm . I'm sure you can find other similar DC-DC converters.
Regards,
Mel
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Re: Ask Mel Berman, from TDK-Lambda a question
atvortke Dec 28, 2010 3:53 PM (in response to nlarson)Hi, Mel, i have car audio amplifier , and in it is blown FEP16DTD. And i cannot get it in EUROPE, maybe you could help me?
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Re: Ask Mel Berman, from TDK-Lambda a question
mberman Jan 5, 2011 1:13 PM (in response to atvortke)Hello atvortke,
We do not supply components, but there are a number of distributors who have this P/N in stock, including Newark.
Regards,
Mel
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Re: Ask Mel Berman, from TDK-Lambda a question
australianurbangolf.com Jan 17, 2011 8:06 PM (in response to nlarson)Or just search google.
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Re: Ask Mel Berman, from TDK-Lambda a question
Miki Prascak May 25, 2011 3:43 AM (in response to nlarson)Hi Mel,
I'm using the FPS1000-48 AC-DC supply (two of them to supply symetrical +/-55V)
And now I'm redesigning the power source and want to get rid of the proprietary connector on the FPS version. I've found the RFE series power supplies with screw terminals.
Can you please confirm that the RFE1000-48-YRFE1000-48-Y could be a direct replacement for the FPS1000-48 ?
If not can you suggest a 1000W power supply for my scenario? (2 modules in series with center tap to make symmetrical output voltage, voltage trimable up to ~60V)
(I'm using the supply to power our industrial amplifier (6x300VA) for a synthetic mains generator, so the current draw from the supplies copies a 50Hz sine wave.)
Thanks,
Miki
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Re: Ask Mel Berman, from TDK-Lambda a question
mberman May 25, 2011 11:09 AM (in response to Miki Prascak)Hi Miki,
We confirm that the RFE1000-48-YRFE1000-48-Y is functionally the same as the FPS1000-48 except for the differences in the packaging of these two power supplies. We have other 1000W, 48V output power supplies, but if the FPS or RFE series work for your application, it may be best to stay with them.
Since you are located in Slovakia, you are welcome to visit our European web site at: http://www.lambda-gb.com/public/index.aspx if you want to explore other 1000W power supplies.
Kind regards,
Mel
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Re: Ask Mel Berman, from TDK-Lambda a question
Miki Prascak May 26, 2011 4:00 AM (in response to mberman)Thanks for your quick reply.
Since I'm redesigning the whole unit I'm free to completely change the power supplies. So if you have a suggestion for a more suitable power supply series (i.e. cheaper ) I'd be glad to hear about it.
Currently our production version uses two FPS modules mounted in our custom 2U 19" rack enclosure (with some additional cooling). So there is plenty of space available in the box. The FPS series performed well for our purpose so far. The only annoyance is the loudness of the cooling fans even without load (not to mention full load - first time I've applied full load I thought its preparing to take off and fly home to your factory ).
thanks
--
miki
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Re: Ask Mel Berman, from TDK-Lambda a question
mberman May 26, 2011 1:38 PM (in response to Miki Prascak)Hi Again Miki,
You may want to look at TDK-Lambda's model SWS1000L-48SWS1000L-48 power supplies. These are not rack mountable, but may be of interest since they have low acoustical noise. For specs and details please go to this web site: http://www.lambda-gb.com/public/product_details.aspx?cid=1&t1type=acdc&scid=281
For price and availability, here is an e-mail address you can use:
powersolutions@uk.tdk-lambda.com
Best regards,
Mel
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Re: Ask Mel Berman, from TDK-Lambda a question
jlsanchez@clock-technology.com Jun 23, 2011 3:31 AM (in response to nlarson)Hi Mel,
what is a good choice to design a Led Power Supply with 115-230V input and 12V output (constant voltage) with hight power factor and efficiency? I'm looking for a reference design or tool to obtain up to 60W (ON semiconductor, Linear T., T.I., ST...) for a test. Can you help me?
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Re: Ask Mel Berman, from TDK-Lambda a question
mberman Jun 23, 2011 12:36 PM (in response to jlsanchez@clock-technology.com)Hello,
Any of the companies you mention above are good sources. I ran across a novel LED driver circuit that does not use electrolytic caps (which dry out over time). You can review this design at the following web link:
http://www.epcos.com/web/generator/Web/Sections/Components/Page,locale=en,r=263282,a=2042462.html
Also, you might consider a ready-made power supply since they come with Safety Certs that you must have when operating off the AC line.
Some suggested models are listed at this site: http://us.tdk-lambda.com/lp/products/ledsigns.htm .
Good luck with your project.
Mel
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Re: Ask Mel Berman, from TDK-Lambda a question
geoffcmitchell Jun 24, 2011 5:03 AM (in response to nlarson)Linkswitch 613.... I would just like to purchase a ready made ac-dc converter modual; universal mains in and 5V 1W out worst. Do these exist in a small outline (vis. the off the shelf modual that works at 72Vdc in)? I can just shoehorn in a setup using the linkswitch 613 which is more powerful than I need.
The 613 worked, but I had to play with that clamping /damping cct. to get a proper result at each end of the mains-in spread. I'm using the recommended cct.... why do these never quite work?
What might I have over-looked?
Geoff
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Re: Ask Mel Berman, from TDK-Lambda a question
mberman Jun 24, 2011 9:47 AM (in response to geoffcmitchell)Hi Geoff,
I don't have experience with the Linkswitch 613. But if you Google "AC-DC 5V 1W power supply" you will see some possible alternates. Most commercial AC-DC power supplies begin at 5W of output power. I know this is more power than you need, but it may be a more reliable solution for you. You may want to review a 5V, 5W power supply (model KPSA5-5) at this website: http://us.tdk-lambda.com/lp/products/kpsa-series.htm
Best regards, Mel
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Re: Ask Mel Berman, from TDK-Lambda a question
geoffcmitchell Jun 24, 2011 11:10 AM (in response to mberman)Many thanks Mel,
It would do me good to get my head around those clamping/ damping ccts. though. E.G it says use a 820pF cap rated 1KV, but they are not that well stocked so I've used a 1n 1KV version.... should I adjust the TC of its parallel resistor for the same value? i.e. how critical is this cap value?
Have you tried getting pulse rated capacitors just lately.... they are becoming made-to-order!?
Geoff
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Re: Ask Mel Berman, from TDK-Lambda a question
mberman Jun 24, 2011 11:28 AM (in response to geoffcmitchell)Hi Geoff,
You should be able to get assistence with your LinkSwitch questions at this website:
http://www.powerint.com/en/products/linkswitch-family/linkswitch-ii
Yes, capacitors of all types have become scarce, due in part to the Japanese earthquake and tsunami.
Hopefully, this situation will clear up soon.
Mel
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Re: Ask Mel Berman, from TDK-Lambda a question
geoffcmitchell Jun 24, 2011 6:54 PM (in response to mberman)Thanks Mel,
Geoff
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Re: Ask Mel Berman, from TDK-Lambda a question
smsbeam Jul 26, 2011 2:05 PM (in response to nlarson)Mel,
I'm using an LMC7660 charge pump to provide power to an LM4562NA/NOPB.LM4562NA/NOPB. op amp in an audio EQ. The problem is the LMC7660 operates at 10khz and provides a whine onto Vee. My question is ; if I use a low pass filter to cut out the 10khz what would be the ideal choice of components to remove the hum and try to maintain some sort of efficiency. Ideally squeezing out as much power as I can. I was thinking around R=47ohm (to limit Volt drop) and changing Cr to around 33uf and putting the same filter on the V supply to the charge pump giving good roll off but I don't know what effect this will have on the device ? Any ideas?
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Re: Ask Mel Berman, from TDK-Lambda a question
mberman Sep 16, 2011 10:32 AM (in response to smsbeam)Hi Ben,
We have found that audible noise in power circuits can originate from inductors or transfomers that have too much mechanical clearance between the cores and the windings. You might try substituting these parts in your circuit with others from different vendors to see if the noise is removed. This is the only suggestion I can offer.
Best regards,
Mel
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
Harley Clark Feb 3, 2012 10:26 AM (in response to nlarson)Hi Mel,
Please can you help me choose a suitable switching regulator? I need to step a DC42V lithium ion battery current down to 4.2V to drive a GSM modem. Most of the time the GSM modem only uses about 2mA of power but it occasionally bursts up to 2A for short 4ms periods during transmission. I need the conversion to be as efficient as possible so as not to flatten the lithium ion battery. I tried an Allegro A8499 but it kept cutting out when the 2A transission bursts happened. Do you know any switching regulators that are suitable for this kind of conversion.
Thankyou and best regards,
Harley
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
mberman Apr 2, 2012 10:36 AM (in response to Harley Clark)Hi Harley,
Suggest you try Texas Instruments. There are many manufacturers of step down DC-DC converters that you can contact.
Best regards,
Mel
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
MTSftw Jul 18, 2012 12:00 PM (in response to nlarson)Hi Mel Berman!
I am working with an EL wire. I have set-up a circuit similar to that of Jeri Elsworth EL WIRE POWER SUPPLIES. (link http://www.youtube.com/watch?v=AcXHx5ikjM4) It works great. Now I am looking online to purchase a trasnformer for this circuit so that i can make a friend one too. I can't seem to find any small transfromers. The one I am using currently from salavged parts measuring 14mm X 14mm X 16mm and was PCB mounted. Also I know that this trasnformer has a single coils on each side with one being centered tapped. Originally the circuit I pulled the transfromer from was battery operated with an input of 3VDC and step-up to 115VAC. (where the EL wire used to go)
Since I wasn't satisfied with it's brigness level on the original circuit. I used Jeri's circuit to provide the system with 5VDC and stepped up to 140VAC for the EL wire. I have also set up the time constant so taht the resistor is variable with the Capacito making the frequency adjustable. Now the big question is, what sort of power transfromer would you recomend for this project.
Thanks in Adavanced,
-Josue Cruz-Lambert
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
mberman Jul 18, 2012 12:19 PM (in response to MTSftw)Hi Josue,
Sorry, but we cannot assist you regarding EL power supplies, which require AC outputs and are very specialized for that application.
We are here to help "users select the proper AC-DC or DC-DC power supply for their application."
If ever you need a conventional AC-DC power supply or DC-DC converter, please visit our website to review the many products we have available: http://www.us.tdk-lambda.com/lp/
Kind Regards,
Mel
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
MTSftw Jul 18, 2012 12:42 PM (in response to mberman)Thank you Mel!
I really appreciate your quick reply!
Best Regards, Josue Cruz-Lambert
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
jmeiners Aug 15, 2012 11:46 AM (in response to nlarson)Can I ask a question of Mel Berman of TDK Lambda,
About high frequency ac input rectification?
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
mberman Aug 15, 2012 12:48 PM (in response to jmeiners)Hi John,
TDK-Lambda designs and manufacturers AC-DC power supplies that typically work with nominal input frequencies from 50 to 60 Hz. Some of our products will operate with AC input frequencies up to 400 Hz, which is used in Avionic and some MIL applications. For Avionic applications there is a move towards using AC inputs up to 800 Hz. At present we do not deal with frequencies above 440 Hz. However, when working with these higher input frequencies, the use of synchronous rectification, using MOSFETs, is required to meet the switching speeds and to maximize the efficiency of the high speed rectification stage. Attached is a web link to an article about the move from 400 Hz to 800 Hz for future Avionic applications. Also attached is a link to information about synchronous rectification. Hope this helps.
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
jmeiners Aug 15, 2012 12:58 PM (in response to mberman)Hi Mel,
It is helpful, thanks very much.
I would still wonder, however, if you can compete in efficiency and cost with fast recovery diode modules to the MOSFETs.
If you can answer that...?
John Meiners (516) 625-1313 Ext. 113
SanRex Corp
Semiconductor Sales Division
50 Seaview Boulevard, Port Washington, NY 11050
Please visit our web site at: sanrex.com
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
mberman Aug 15, 2012 1:31 PM (in response to jmeiners)Hi John,
Relative to efficiency, synchonous rectification with MOSFETs beats diodes, even with Schottky diodes.
Most new designs for high efficiency power supplies employ synchonous rectification with MOSFETs.
However, if lower cost and ease of design are your main considerations, Schottky diodes should be considered.
Here is a link to a good article about this subject.
http://en.wikipedia.org/wiki/Active_rectification
Lots more info is available online via Google searchs.
Best Regards,
Mel
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
jmeiners Aug 15, 2012 1:42 PM (in response to mberman)Very good Mel, thanks again.
By the way, we are a supplier to TDK-Lambda for 3 phase diode rectifier bridges!
Thank you,
John Meiners
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
mberman Aug 15, 2012 3:07 PM (in response to jmeiners)Hi John,
Yup, many TDK-Lambda power supplies employ conventional diodes for input rectification. As I mentioned, in cases where the overall efficiency of the power supply is a "prime concern" the use of more advanced components and synchronous rectification techniques become a viable and more costly design consideration.
Thanks,
Mel
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
jmeiners Aug 15, 2012 3:35 PM (in response to mberman)Say Mel, ...do you work for TDK in Neptune, NJ, or for element 14?
Thank you,
John
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
mberman Aug 15, 2012 4:14 PM (in response to jmeiners)John,
TDK-Lambda Americas located in Neptune, NJ is our "High Power Division" and designs/manufactures different power products than we do. http://us.tdk-lambda.com/hp/
I work for TDK-Lambda Americas in San Diego, CA, which is called the "Low Power Division."
http://www.us.tdk-lambda.com/lp/
Included above are links to both TDK-Lambda Americas division's web sites where you can see the differences in our product lines.
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
jmeiners Aug 15, 2012 4:40 PM (in response to mberman)Thank you Mel,
John
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
WJ_ANG Nov 23, 2012 12:02 AM (in response to nlarson)Hi, I would like to have a high dc voltage output of 5KV and low ampere, how can i fabricate a dc-dc converter?
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
mberman Nov 27, 2012 1:25 PM (in response to WJ_ANG)Hi John, As you know, 5KV is a very dangerious high voltage. I do not get involved with high voltage dc-dc converters. However, you can find many devices via search engines (e.g., Google, IE). I would suggest you purchase a predesigned and fabricated dc-dc converter. Regards, Mel
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
l1t7l3ph0o7 Apr 29, 2013 7:08 PM (in response to nlarson)Hi, I'm not sure if I'm asking this in the right place, but here goes.
Does anyone know where I can find a battery clip that holds 4 cr2032 button cells?
I've been looking around and can only find ones that hold a single cell
anything constructive appreciated Thank you
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
ckambiselis Jul 15, 2013 2:24 PM (in response to nlarson)Hello Mel,
I am building a DC-DC converter to convert the 14.8v 6A power coming from a professional camera battery to 9V 2.5A used by a DLR, I am trying to build this converter using the LM317 since it's the only easily available power regulator (which I don't have to order 2500pcs to place an order), the problem is the LM317 can only output 1.5A max, can I build the circuit using 2 of them and connecting the outputs of each circuit in paralel to get 9V 3A, is there going to be any kind of problem that may fry the camera?
Thank you
Oscar
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
Nortski Jul 18, 2013 11:14 AM (in response to ckambiselis)Hello Oscar,
That question would be best answered by Fairchild or TI. You will probably run more of a risk of overheating the 317 regulators if you just parallel them. If the camera is expensive, then I would suggest putting a suitable fuse in the input and a nice suitable 5W zener across the output. If a linear regulator fails short circuit, you will be protected.
David
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
eeyore65 Nov 19, 2013 7:06 PM (in response to nlarson)Can i use a buck converter and boost converter in the same circuit ? I want to boost 4 nicad cells up to maybe 9 to 12 volts and use that for 1 part of the circuit, then drop it down to 5 volts for another part of the circuit. I am thinking of doing it this way so I can get a steady voltage supply to the different parts of the circuit. Or should i just start with 12 volts and then drop it down to 5 volts ?
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Re: Ask Mel Berman, from TDK-Lambda a question
Nortski Nov 25, 2013 2:30 PM (in response to eeyore65)Hi Charles,
Everytime you convert the power you loose efficiency, so I would start with 12V and drop down.
Thanks
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Re: Ask Mel Berman, from TDK-Lambda a question
wiinick Nov 24, 2013 2:48 AM (in response to nlarson)I am building an Altoids USB power supply. I have an LM7805 converting down to 5v at 1 amp. But It's like 40% efficient. I am getting an LM2596 which has 150Khz oscillator and 3amp output. Now would charging an Ipod at 3 amps be bad for the battery, or would the ipod just take 1amp and leave the other 2 amps alone. Because most USB ports dont output more than 1 amp. If this is bad for USB devices with batteries, How would I lower the amperage but not the voltage?
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Re: Ask Mel Berman, from TDK-Lambda a question
Nortski Nov 25, 2013 2:37 PM (in response to wiinick)Hello Nicholas,
Over charging batteries is not a good idea!
Constant voltage battery chargers can regulate the charging current by reducing the output voltage, but that needs some external circuitry and a current sense circuit.
I would suggest ask the folks at TI
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
rmele14 Mar 21, 2014 6:36 PM (in response to nlarson)Hi Mel,
I hope you're still answering questions here. I want to build a simple unregulated DC supply for a 115vdc 1.4 amp motor. From what I've gleaned from the web, I need about a 150vdc 1000 uF filtering cap. These seem to be very expensive! $200-300. Am I looking at the wrong type of caps? Do I need a cap at all?
Thanks,
Ron
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
Nortski Mar 21, 2014 6:57 PM (in response to rmele14)
Hello Ron,Mel is now happily retired!
Try this part 108LBB200M2DE - ILLINOIS CAPACITOR 108LBB200M2DE - CAPACITOR ALUM ELEC 1000UF 200V 20%, SNAP-IN | Newark element14 US
Price
Quantity List Price 1 - 24 $5.28 Best regards,
David
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
rmele14 Mar 21, 2014 7:27 PM (in response to Nortski)Thanks David,
Exactly what I need. Can you point me to a design primer to learn a little about specifying parts like this?
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Re: Ask Mel Berman, from TDK-Lambda a question about AC-DC power supply and DC-DC converter applications
Nortski Aug 7, 2014 9:22 AM (in response to rmele14)Hello Ron,
This link may help http://www.electronics-tutorials.ws/capacitor/cap_3.html
Best regards,
David
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