Is this a good regulator.

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Creative25
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Is this a good regulator.

Post by Creative25 »

Hi I just found this economic regulator on the net.
http://semicon.njr.co.jp/njr/hp/fileDow ... diaId=8403
What is interesting on the device is that it is claimed you can have an input voltage of up to 30 Volts
Has anyone tried one of those?
Would they be suitable for a Microchip on the LED Camping light?

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Uli

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Re: Is this a good regulator.

Post by Enamul »

Hi Uli,
What is interesting on the device is that it is claimed you can have an input voltage of up to 30 Volts
I can't find that in the datasheet..as it says maximum input voltage is +9V.
Another issue is maximum current is only 150mA but that is enough for just a microchip..
But interesting issue is control feature.
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Re: Is this a good regulator.

Post by Creative25 »

Sorry I pasted the wrong link.
Here is the correct one.
http://media.digikey.com/pdf/Data%20She ... M78L00.pdf
Best Regards:
Uli

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Re: Is this a good regulator.

Post by Enamul »

Hi ULI,
LM78XX series is very popular voltage regulator and can be obtained in LM7805, 06,09,12,15 and 24. Last two digit is the designated output voltage..LM79XX series is it's complementary series for negative supply. The maximum current rating for this regulator in TO220 package is 1 A(theoretical ). But these are fixed voltage regulator. These are popular in making power supply for microchip.
Another two series are LM317 and LM337 which can with stand around 40V in input while can produce output as low as 1.25V to 37V positive and negative respectively. If you want to make any supple like 3.3 V you will get fixed regulator IC as well but for other variable voltages LM 317 is great and can provide 1.5A maximum (theoretical ) current.
http://www.ee.buffalo.edu/courses/elab/LM117.pdf
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Re: Is this a good regulator.

Post by Creative25 »

Is there a quality difference between the different makes of the LM78XX series?

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Re: Is this a good regulator.

Post by Enamul »

Hi ULI,
As long as you are buying from good quality IC from even different makers..it shouldn't differ too much. But the issue is the place where are you buying from as some Chinese ICs are not in good quality.
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Re: Is this a good regulator.

Post by Creative25 »

Do you know if the one I mentioned which is from new Japan Radio
is a good make?

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Re: Is this a good regulator.

Post by Enamul »

Hi
Are you asking about this one..
http://media.digikey.com/pdf/Data%20She ... M78L00.pdf
If so, digikey always supplies good components..that should be good.
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Re: Is this a good regulator.

Post by Desdewit »

Hi Guys

I'm using this switching regulator from RS components; it's a bit expensive but works like a dream 6.5V to 36V input with 5V 9W output. (Search for switching regulator from Traco Power on rs web site) :wink:

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Re: Is this a good regulator.

Post by Benj »

Hello,

I find that standard low drop out regulators work well with lower input voltages eg 5V down to 3V3 or at a push 12V down to 5V. The voltage is converted to the output by dropping the rest of the voltage across a load which means that the higher the input voltage the hotter the regulator is going to run. This also means that your maximum throughput current will be much lower then expected and the theoretical limit is normally only applicable if your using big heatsinks etc anyway.

I have now started using a switch mode regulator on some of the E-blocks and this allows the regulator to run cool at higher voltages and currents. Also because of the nature of the device the larger the input voltage is the less current you consume. See the EB069 datasheet if you want a schematic.

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Re: Is this a good regulator.

Post by Creative25 »

Desdewit wrote:Hi Guys

I'm using this switching regulator from RS components; it's a bit expensive but works like a dream 6.5V to 36V input with 5V 9W output. (Search for switching regulator from Traco Power on rs web site) :wink:
Hi Thanks for the Ideas.
I checked them out.
On some of them it says unregulated, what does this mean?

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Re: Is this a good regulator.

Post by Creative25 »

Benj wrote:Hello,

I find that standard low drop out regulators work well with lower input voltages eg 5V down to 3V3 or at a push 12V down to 5V. The voltage is converted to the output by dropping the rest of the voltage across a load which means that the higher the input voltage the hotter the regulator is going to run. This also means that your maximum throughput current will be much lower then expected and the theoretical limit is normally only applicable if your using big heatsinks etc anyway.

I have now started using a switch mode regulator on some of the E-blocks and this allows the regulator to run cool at higher voltages and currents. Also because of the nature of the device the larger the input voltage is the less current you consume. See the EB069 datasheet if you want a schematic.
Hi Benj, this one seems quite an easy one to do.
How many amps can this one supply? Does it require a ground plane?
I will try it in the future.

For the project I am doing right now I think the 78L05 regulators are fine I supply One Pic12f1822 the pic powers one Green 20mA led and a PWM signal. I think for such small currents a linear regulator is fine even with a 12 Volt supply.

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Re: Is this a good regulator.

Post by Enamul »

I believe you can go for one like this...
http://uk.rs-online.com/web/p/switching ... s/6664379/

Ben's recommended one is also nice..3.3V, 5V, 12V, 15V, and adjustable output
versions and Guaranteed 1A output current; Wide input voltage range, 40V up to 60V for HV version.
http://www.ti.com/lit/ds/symlink/lm1575.pdf
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Re: Is this a good regulator.

Post by FaithBartlett »

If it really provides 6.5V to 36V input with 5V 9W output then I will also use switching regulator from RS components.

leased line

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Re: Is this a good regulator.

Post by Steve001 »

i have some Traco units fitted to some of my proto type pcbs and am happy with them , i many use them because some have output short circuit protection which makes them ideal for experimenting :) helping to prevent expensive accidents :lol:

here they are at farnell

http://uk.farnell.com/dc-dc-converters- ... oard-mount

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Re: Is this a good regulator.

Post by Creative25 »

Enamul wrote:I believe you can go for one like this...
http://uk.rs-online.com/web/p/switching ... s/6664379/

Ben's recommended one is also nice..3.3V, 5V, 12V, 15V, and adjustable output
versions and Guaranteed 1A output current; Wide input voltage range, 40V up to 60V for HV version.
http://www.ti.com/lit/ds/symlink/lm1575.pdf
I just had a look at the datasheet of the regulator from Texas Instruments.
On the data sheets there is always a question on my mind.
It gives you a graph with blocks of what value of Inductor to use. According to voltage and current.
Now my question is this If I would use an Inductor with ha higher value than recommended, what will it do? Will it be less efficient, or is it just a question of cost and size of the regulator?
What if I want to make an adjustable power supply for testing purposes. For example for the purpose of adjusting a threshold voltage of a circuit board that does not have a display. Would I have to use the highest inductor value that could possibly be needed?
Or are these type of regulators not suitable for adjustable power supplies?

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Re: Is this a good regulator.

Post by Steve001 »

page 19 gives an explanation of inductor sizing there is also some software too

http://www.ti.com/tool/switchersmadesimple-sw

hope this is of some help it's not a device i am familier with

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Re: Is this a good regulator.

Post by Brendan »

An old post but for reference...

Inductor selection is relatively complex for these types of regulators.

The buck mode regulator first charges the inductor in series with the load (transistor on), the ramp current speed determined by the value (reactance) of the inductor. When the charge path is removed (transistor off), the inverse voltage from the inductor discharges into the load via the forward-biased diode at this point. As the mark-space ratio has limited range (effectively governed by the peak switching speed of the driving transistor), the inductor needs to be chosen based on available inductor charging voltage (input voltage) and the load current. For load currents subject to significant variation, transient response is another consideration also affected by choice of inductor and switching speed, and inductor DC resistance affecting efficiency. It's therefore a balancing act, hence the recommended range of values dependent on application.

If you're minded to design a 'proper' voltage-variable lab supply, I would recommend using the buck regulator to pre-regulate the supply to a follow-on voltage-adjustable linear regulator to limit dissipation in the latter. The inductor should be selected against maximum design output current and unregulated input voltage. The linear regulator would therefore take care of ripple noise rejection and provide much better load regulation over a considerably greater variation in load conditions.

With a PNP transistor base connected via resistor to the linear regulator output, the collector taken to the buck regulator feedback pin, and the emitter taken to the linear regulator input, the buck regulator will automatically adjust its output tracked against the setting of the linear regulator. With another resistor between base and emitter, the transistor Vbe may then be used as a reference to increase the required (constant) headroom voltage for the linear regulator - particularly if using a non-LDO type. In this configuration, add a further resistor from buck regulator feedback pin to ground to ensure a pull-down path.


All the best,

Brendan

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