make 13 volt from Usb

Go To Last Post
17 posts / 0 new
Author
Message
#1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

hi i have a board that in some cases it need 13 volts and i want use usb port for power supply of course it dosent need so much current, please tell how can i convert 5 volt to 13 v???

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

How much current?
Switching power supply? capacitive charge pump?

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

it dosent need so much current about 20ma both at first capacitive then switching the cheaper is better.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Maxim MAX632?

Leon

Leon Heller G1HSM

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Or LT1615-1? http://www.linear.com/pc/product...

LT1615-1 does however require an external schottky "catch" diode as opposed to MAX63x that have an intenal "catch" diode. Both require an external inductor.

MAX632ACSA+ http://search.digikey.com/script...
LT1615ES5-1#TRMPBF http://search.digikey.com/script...

Of course you could also modify a charge-pump voltage doubler into a voltage tripler by adding extra diodes and capacitotrs.
Read the section "Charge-pump tricks": http://www.maxim-ic.com/appnotes...

If 12V out had been enough the easiest and cheapest would probably have been to use the MAX662A regulated +12V charge-pump (12V, 30mA Flash Memory Programming Supply) http://www.maxim-ic.com/quick_vi...

You can even steal some power from a RS232 driver IC, these have built-in charge pumps.
If you are trying to get 13 Vpp to program a PIC you can steal the power from an RS232 driver IC that might already be used in the circuit for serial communication.

http://www.electro-tech-online.c...

William At MyBlueRoom wrote:
Pommie wrote:
The data sheet for the 18F chips states 300uA for Vpp current and 10mA for Vdd.

Great, that's easy. I can get 1 to 2 ma without effort.

http://www.geocities.com/constan...
Quote:

You could also simply have your AVR generate a square wave output and add an external voltage tripler by using a few diodes and capacitors.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

ON Semiconductor NCP1403 is a much cheaper alternative, to the above mentioned Maxim and Linear devices.
http://www.onsemi.com/PowerSolut...
http://search.digikey.com/script...

You could also use a National LM27313 boost converter, while more expensive than NCP1403 this is also a lot cheaper than the Maxim and Linear devices mentioned above.
http://www.national.com/pf/LM/LM...
http://search.digikey.com/script...

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

thank you all my friends , adersand yes i want to programe,that schematic max232 is so good i want use it for this circuit,instead of trans use USB, what do suggest?
http://hmdtop.persiangig.com/89sch.gif

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

So you are going to use this VPP voltage for an AT89C51 programmer? VPP for AT89C51 is specified to be 11.5V - 12.5V, so why do you want 13V? And IPP is specified to max 1mA for AT89C51.

I don't understand the part about RS232 and USB in your last post. Is this programmer going to be connected to RS232 or USB or both?

How is the programmer powered? From an USB connector or a DC jack?

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I think he wants to use the schematic in the link he provided, but maybe remove the MAX232, use a FTDI FT232 for that and then he needs a way to get 13V for the VPP generator. Just a guess :roll:

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I saw bar code scanners, using RS232 port but powered from the keyboard plug, since old days didn't have USB connectors. I think it is the case.
To OP: since you have a lot of possibilities for a square signal, I think a pump charge is a good choice. 5V times three, minus some diodes, will give you exactly what you need.
George.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

so my friend this circuit need a an outer power supply like a transformer to make forexample 220v to 12v ac so now i want use only usb voltage instead of that and in this case we need 11.5 ~ 12.5v or 13v is better so how can we make 13 volt from usb?

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

hmdtop wrote:
so how can we make 13 volt from usb?
By buying or building your own voltage converter. Others have given you a lot of hints and examples how to build your own. If this goes over your head, buy one.

Stealing Proteus doesn't make you an engineer.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

AndersAnd wrote:
ON Semiconductor NCP1403 is a much cheaper alternative, to the above mentioned Maxim and Linear devices.
http://www.onsemi.com/PowerSolut...
http://search.digikey.com/script...

If you want to go really cheap, there is always the ancient MC34063 http://search.digikey.com/script... But these things require a little bit more love and caring (and external components) then, let's say, something from the more expensive National simple switcher series.

Stealing Proteus doesn't make you an engineer.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

since you requested in large blue text i would suggest you use the 34063 type.

oddbudman

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I think that the AVRDoper project generates a 12(13?)v supply using pulses from an AVR. This is an HVSP programmer that uses USB. If I remember correctly, it modifies the duty cycle(?) to maintain a specific voltage. It's probably worth a look for the OP.

Nigel Batten
www.batsocks.co.uk

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

thank you all my friends i have some condition here in my country i cant find what ever i see in the web sites so it make those part that is not here expensive,i thought if i make that voltage with lm2576 what do you think about that dose it work or not? it cost something about 2$ here for me ofcourse some one suggest me to use the max232 output voltage ?

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

hmdtop wrote:
i thought if i make that voltage with lm2576 what do you think about that dose it work or not?

How will you boost the voltage with a LM2576?
It's a Step-Down converter, not a boost converter: http://www.national.com/mpf/LM/L...

hmdtop wrote:
it cost something about 2$ here for me ofcourse some one suggest me to use the max232 output voltage ?

Sorry what was your question?