Sharing throttle position sensor signal

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rayhall

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Hello Everyone,

I need to share the throttle position sensor signal going to the engine ECU with a central differential controller. If I connect both controllers to the TPS (throttle position sensor) the engine ECU reads as it should until I start the engine. Then the TPS value changes by about 1% to 2%.

I have made up this circuit that sort of works. The problem is the voltage into the diff controller is not exactly the same across the 0 to 5 volt signal range of the TPS.

Ray.

**broken link removed**
 
You need a rail-to-rail input and output op amp, connected as a voltage follower (unity gain, noninverting), that will work with a 5V supply. If you don't know what that means, we can draw a schematic. Can you use surface mount components, or do you need to stick to through-hole parts? Surface mount units are probably easier to find. Maybe one of the guys here can suggest a thru-hole part if you need one.
 
Ron,

You need a rail-to-rail input and output op amp, connected as a voltage follower (unity gain, noninverting)
Click to expand...

Thanks for the reply. Surface mount components are not a problem. I know basic electronics, but most of this statement is a bit over my head. Any help in the right direction would be good.

Thanks

Ray
 
rayhall said:
Ron,



Thanks for the reply. Surface mount components are not a problem. I know basic electronics, but most of this statement is a bit over my head. Any help in the right direction would be good.

Thanks

Ray
Click to expand...
I'll try to select an op amp for you. What parts supply houses do you have access to? Or, you might be able to get samples from Maxim.
 
Sorry I disappeared. Sleep intervened.
The TLV2371 appears to be available from Farnell. I didn't check the other vendors. If you can't get it, there are others.
 

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Roff said:
Sorry I disappeared. Sleep intervened.
The TLV2371 appears to be available from Farnell. I didn't check the other vendors. If you can't get it, there are others.
Click to expand...

Hi Ron,

Could you point me in the right direction, i need to create the same circuit and I only have limited access to components and cannot get theTLV2371 in the time I have available could you suggest a suitable replacement op amp that I could get from jaycar.com.au or altronics.com.au

At the moment I have the same circuit using a CA3140 op amp but the output seems to be scaled. At .45v in it matches but at a 4.5v in I'm only getting 2.6v out

Regards

Daryle
 
The 3140 does not have 'rail-to-rail output' capability. Try googling for opamps which do.
 
**broken link removed** is a dual op amp that should work. If you don't use one of the op amps in the package, you should stabilize it by connecting it as another voltage follower (output to -input), with the +input connected to the +input of the one you are using. Don't connect the output of the unused op amp to anything else.
Altronics doesn't seem to have anything that will work.
 
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