voltage regulator 5v to 3.3v

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1

hi all,

does anybody have a recommendation for a voltage regulator shifting the
level from 5v to 3.3v? the current i’ll be using will be around 170 mA. so
the voltage regulator’s max supply current could be less than 300 mA.

cheers for the help.

:slight_smile:
const

2

Depends on package. I have some SOT23-5 which should be good for that, and
some TO-220 style as well.On 19 May 2014 17:11, Constantin Popp constantin.popp@gmail.com wrote:

hi all,

does anybody have a recommendation for a voltage regulator shifting the
level from 5v to 3.3v? the current i’ll be using will be around 170 mA. so
the voltage regulator’s max supply current could be less than 300 mA.

cheers for the help.

:slight_smile:
const

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Ben Dooks, http://www.fluff.org/ben/ bjdooks@googlemail.com

3

Constantin,

There are 3.3V regulators in the IC box on the electronics bench in the
Hackspace. Help yourself to one having made a suitable donation and
continue onwards. These are all T0220 devices so are capable of performing
under the conditions you have specified. You may need a heatsink as the
the 1.7V you are reducing will be lost as heat. You will also need to
check the datasheet for the device that you use so that you know what the
pin connections are.

Regards

AlexOn 19 May 2014 17:17, Ben Dooks bjdooks@googlemail.com wrote:

Depends on package. I have some SOT23-5 which should be good for that, and
some TO-220 style as well.

On 19 May 2014 17:11, Constantin Popp constantin.popp@gmail.com wrote:

hi all,

does anybody have a recommendation for a voltage regulator shifting the
level from 5v to 3.3v? the current i’ll be using will be around 170 mA. so
the voltage regulator’s max supply current could be less than 300 mA.

cheers for the help.

:slight_smile:
const

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Ben Dooks, http://www.fluff.org/ben/ bjdooks@googlemail.com

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4

hi all,

does anybody have a recommendation for a voltage regulator shifting the
level from 5v to 3.3v? the current i’ll be using will be around 170 mA. so
the voltage regulator’s max supply current could be less than 300 mA.

cheers for the help.

:slight_smile:
const

5

hi ben and alex,

thanks for the recommendations. will have a look at these.

i wonder, though, if there might be a better way of dealing with this. i
would like to use the wiznet5200 controller (within the wiz820 package)
powered by usb. so i thought i need to convert the usb’s 5v to 3.3v the
wiznet wants. is there a more efficient way to do the power conversion
without having to heat the room due to voltage regulation?

:slight_smile:
cont

6

Constantin you need a logic level converter…not a voltage regulator. You
can use resistors or transistors or a special integrated circuit for this
purpose:

http://www.adafruit.com/datasheets/sn74lvc245a.pdf - a device for
performing the logic level conversion - Easiest method

http://letsmakerobots.com/node/34444 - a circuit using transistors and
resistors for performing the conversion - Hardest method

https://www.sparkfun.com/products/12009 - a premade breakout board using a
similar circuit for performing the conversion - Another easy method

I would suggest buying a breakout board for doing what you require…

Cheers

AlexOn 20 May 2014 13:11, Constantin Popp constantin.popp@gmail.com wrote:

hi ben and alex,

thanks for the recommendations. will have a look at these.

i wonder, though, if there might be a better way of dealing with this. i
would like to use the wiznet5200 controller (within the wiz820 package)
powered by usb. so i thought i need to convert the usb’s 5v to 3.3v the
wiznet wants. is there a more efficient way to do the power conversion
without having to heat the room due to voltage regulation?

:slight_smile:
cont

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7

You could use a switching regulator - this operates on the same principle
as a switch mode power supply and offers much higher efficiencies, at a
slightly increased cost. (I think you can even get drop in replacements for
popular 3-pin regulator packages).

However, there becomes a point where the amount of power wasted would be
too little to worry about - you calculate it like this: (Vin-Vout)*I

So in your case the power wastage is 1.7*0.17 = 0.289W. You can look at the
datasheet for the linear regulator you’re thinking of using and see whether
a heatsink is required to dissipate that much heat.On Tue, May 20, 2014 at 1:11 PM, Constantin Popp constantin.popp@gmail.comwrote:

hi ben and alex,

thanks for the recommendations. will have a look at these.

i wonder, though, if there might be a better way of dealing with this. i
would like to use the wiznet5200 controller (within the wiz820 package)
powered by usb. so i thought i need to convert the usb’s 5v to 3.3v the
wiznet wants. is there a more efficient way to do the power conversion
without having to heat the room due to voltage regulation?

:slight_smile:
cont

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8

hey alex and rowan,

thanks a million for the further suggestions.

not sure if the logic level shifter is what i need. the wiz820 module would
be hooked up to a teensy 3.1 which operates in 3.3 v. so the logic signals
between the teensy and the wiz820 would be the same. the thing is that i
can’t power the wiz820 module from the teensy directly as it doesn’t
provide enough current (the wiz820 consumes up to 170 mA - the teensy only
allows up to 100 mA). but it does pass through the voltage coming from the
usb. hence my idea of putting some kind of magic voltage changer in there.
:slight_smile: but maybe that’s not really possible in the end anyways. there’ll also
be 16 multiplexed leds, 1 led, 4 to 5 multiplexer ic’s and a small lcd
display. i guess that’s too much for the 500 mA from the usb anyways… :frowning:
(will have to calculate that, too.)

good tip with the breakout board though. i just had a look at the
breadboard power supply board from sparkfun. for the final design i would
just have to incorporate it’s schematics in the complete design. hm…

thanks for the tips, too, rowan. i’ll have a look for this, too. and thanks
for the power/heat dissipation formula. very useful. :slight_smile:

cheers,
constOn 20 May 2014 14:31, Alexander Lang alexanderlang1980@gmail.com wrote:

Constantin you need a logic level converter…not a voltage regulator.
You can use resistors or transistors or a special integrated circuit for
this purpose:

http://www.adafruit.com/datasheets/sn74lvc245a.pdf - a device for
performing the logic level conversion - Easiest method

http://letsmakerobots.com/node/34444 - a circuit using transistors and
resistors for performing the conversion - Hardest method

https://www.sparkfun.com/products/12009 - a premade breakout board using
a similar circuit for performing the conversion - Another easy method

I would suggest buying a breakout board for doing what you require…

Cheers

Alex

On 20 May 2014 13:11, Constantin Popp constantin.popp@gmail.com wrote:

hi ben and alex,

thanks for the recommendations. will have a look at these.

i wonder, though, if there might be a better way of dealing with this. i
would like to use the wiznet5200 controller (within the wiz820 package)
powered by usb. so i thought i need to convert the usb’s 5v to 3.3v the
wiznet wants. is there a more efficient way to do the power conversion
without having to heat the room due to voltage regulation?

:slight_smile:
cont

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9

Constantin…

You don’t power the wiz280 module from the teensy you power them both from
the same power supply but control the wiz280 from the teensy. I will draw
you a diagram…hopefully it will make things clear.

Cheers

AlexOn 20 May 2014 18:55, “Constantin Popp” constantin.popp@gmail.com wrote:

hey alex and rowan,

thanks a million for the further suggestions.

not sure if the logic level shifter is what i need. the wiz820 module
would be hooked up to a teensy 3.1 which operates in 3.3 v. so the logic
signals between the teensy and the wiz820 would be the same. the thing is
that i can’t power the wiz820 module from the teensy directly as it doesn’t
provide enough current (the wiz820 consumes up to 170 mA - the teensy only
allows up to 100 mA). but it does pass through the voltage coming from the
usb. hence my idea of putting some kind of magic voltage changer in there.
:slight_smile: but maybe that’s not really possible in the end anyways. there’ll also
be 16 multiplexed leds, 1 led, 4 to 5 multiplexer ic’s and a small lcd
display. i guess that’s too much for the 500 mA from the usb anyways… :frowning:
(will have to calculate that, too.)

good tip with the breakout board though. i just had a look at the
breadboard power supply board from sparkfun. for the final design i would
just have to incorporate it’s schematics in the complete design. hm…

thanks for the tips, too, rowan. i’ll have a look for this, too. and
thanks for the power/heat dissipation formula. very useful. :slight_smile:

cheers,
const

On 20 May 2014 14:31, Alexander Lang alexanderlang1980@gmail.com wrote:

Constantin you need a logic level converter…not a voltage regulator.
You can use resistors or transistors or a special integrated circuit for
this purpose:

http://www.adafruit.com/datasheets/sn74lvc245a.pdf - a device for
performing the logic level conversion - Easiest method

http://letsmakerobots.com/node/34444 - a circuit using transistors and
resistors for performing the conversion - Hardest method

https://www.sparkfun.com/products/12009 - a premade breakout board using
a similar circuit for performing the conversion - Another easy method

I would suggest buying a breakout board for doing what you require…

Cheers

Alex

On 20 May 2014 13:11, Constantin Popp constantin.popp@gmail.com wrote:

hi ben and alex,

thanks for the recommendations. will have a look at these.

i wonder, though, if there might be a better way of dealing with this. i
would like to use the wiznet5200 controller (within the wiz820 package)
powered by usb. so i thought i need to convert the usb’s 5v to 3.3v the
wiznet wants. is there a more efficient way to do the power conversion
without having to heat the room due to voltage regulation?

:slight_smile:
cont

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