How to get +5V from the +5V Power Source on USB-6501

[Newbie16]

Hi,

The +5V power source output on my USB-6501 is reading 4.74V and not the +5V I would like. I know the reason can be the 

USB power supply but is there a method of getting +5V despite this lower voltage. Thank you.

Regards,

Newbie16 

[Henrik_Volkers]

That's what the spec is telling you:

The voltage source provided by the USB host. The voltage
is nominally 5 V, but varies from system to system.

Easiest way to go would be an additional 5V supply (Check and use a second USB 5V on your PC?)

Next would be a DC-DC converter.

[Newbie16]

Hi,

Yes I have looked at a DC-DC converter, something like the one below. Hopefully it will do the job, thanks.

http://radionics.rs-online.com/web/p/isolated-dc-dc-converters/4735340/?searchTerm=473-5340&relevanc...

[Henrik_Volkers]

The question is : Why can't you use the 4.75V and need 5V?

AND

The spec of the DC-DC converter tells about a 0.1V ripple ...  will you be happy with that?

[Newbie16]

I'm running the 5V (or 4.75V) into a MAX680 +5 to +/-10V IC to power an op amp that needs to output +/- 10V for a motor controller signal. If I can't

reach 10V I cannot get max. speed from the motor, at the moment, as you can guess, I can only get +/- 9.4-9.5V so trying to work out the cheapest

alternative (project objective is low cost, minimal parts)

Thanks for checking the spec, I will have to check out the effect of the ripple, I might get the DC-DC converter, I have not

used one before so would be interesting to test.

[crossrulz]

I would just get on Digikey and search for a power supply that can do +/-10V.  Then it is independant of the USB.  They are usually pretty cheap.

[Henrik_Volkers]

better be a +-12V supply giving you some headroom for an output OP and kick out the MAX680 😉 (but we have DIO only!!! )

Again: What do really need? And what do you have?

  Just a full power on for the motor control?  That can be done with two DIO, opto couplers and (the usually provided) +-10V of the motor controller 😄

One DO for power, one for direction!! 

[adlb]

Hi Newbie16,

Another option would be to use an externally powered usb hub with a more reliable voltage supply than your pc/laptop can supply.

The best thing as others have mentioned would be a dedicated supply suited towards the motor you have in mind.

Regards,