# Thread: 5.5V 2.2W Power Supply???

1. ## 5.5V 2.2A Power Supply???

I have an odd power requirement. I need a 5.5V 2.2A power supply. I've already built a 5v 6A power supply (using a PT6625) and now I guess I need another one.

The PT6625 will need to remain at the same output (it is driving 2 powered hubs).

Someone please help. I would assume I can use an LM1084 with some resistors and caps. Please be specific if making a suggestion, I'm not an electrician or an engineer - thanks!

-HD

2. Originally Posted by joshthepilot
You can hit up radio shack for their variable voltage regulator. It can do up to 1.5 amps which meets your 2.5Watt specs. It uses 2 resistors to set the voltage. Bring a calc with you because I think it says on the back the simple formula. Then you can buy the resistors at the same time.
Thanks for the answer...

Oh Crap - I meant 2.2 Amps...I'm assuming if my device pulled that many amps of this regulator, it would burn out regardless of the size of the heatsink...?

-HD

3. whats wrong with using the same ic (PT6625) for the 5.5 volt's output..?

edit:

i mean, you should be able to use the same regulator (1 for each design )
just put some resistors to vo(adj) pin 14
heres is a datasheet
http://grok.ecn.uiowa.edu/Internal/V...tor_pt6620.pdf

2 edit:
28,4k between pin 14 and Ground (pin 7-10)

4. Josh - thanks for the suggestion. Just to let you know, I'm running (2) 5V 2A usb hubs off the PT6625. I've attached a drawing of what my circuit currently looks like.

If you have time, please modify it and let me know what I need to do to get me 5.5V on one line while keeping 5V on the other 2 lines. Thanks!

5. hd

you can add a 28.4k ohm resistor between the V adj and the ground.

it will give you a 5.5 v out.

6. Originally Posted by xtra
hd

you can add a 28.4k ohm resistor between the V adj and the ground.

it will give you a 5.5 v out.
Thought this would be pretty simple, so I went to Digikey.com and couldn't find any resistor with a value of 28.4k.

Do these exist???? Thanks!

7. you can put resistors in series and parallel to get different values. if you put them in series the values add up... so a 27k and 1.4k in series gives you 28.4k

8. Resurrecting this thread from the dead. Anyone know if the PT6625 can output 10v? If so where do I hook up the resistor? Thanks.

9. NM, started new thread...

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•