is there any circuit or component that may regulate 9v input to both +5v and -5v output at the same time? i need it to drive my op amp. thx.

 

Originally posted by childs72@Mar 31 2006, 03:17 PM
is there any circuit or component that may regulate 9v input to both +5v and -5v output at the same time? i need it to drive my op amp. thx.

[post=15649]Quoted post[/post]​

TI (Texas Instruments) have a power module and I think the number is PT5022. This will take a +5V input and provide a -5V output. If you make a standard power supply to provide +5V and use one of these modules you should be right.

 

Well I am looking at this upside down. Are you married to the particular opamp you have? Will your design allow you to change to a single supply opamp such as an LM324?

 

thx for d PT5022 suggested, however it is still a bit expensive for my project...

by the way my project cannot use single supply op-amp, it is a precision current sink and a precision current source.

 

If you are not overly concerned about power 'hogging' and if your DC offset requirements are not overly critical , you may want to consider using a voltage divider for your 1/2 vcc voltage source. Make the divider so it draws more current than the rest of your circuit, and of cource use bypass caps.

Another thing you may want to do if you can, is to use an opamp as the power source for your 'signal ground' (4.5v)... this would be much more efficient than a voltage divider.

Spoggles

 

Originally posted by childs72@Apr 1 2006, 05:09 AM
thx for d PT5022 suggested, however it is still a bit expensive for my project...

by the way my project cannot use single supply op-amp, it is a precision current sink and a precision current source.

[post=15659]Quoted post[/post]​

Not if you request samples from TI.

 

hi,

maybe you might want to consider using a 555 timer with a 5v zener at its output to come up with a -5vdc.

moz

 

Originally posted by mozikluv@Apr 1 2006, 11:18 PM
hi,

maybe you might want to consider using a 555 timer with a 5v zener at its output to come up with a -5vdc.

moz

[post=15684]Quoted post[/post]​

Another option could be to use a MAX232 RS232 convertor chip. These generate their own -5V which you could probably use.