alright, got the diagram finally...Here's a three opamp (one LM324 package) circuit that will precisely clip the voltage at an adjustable reference input level.
The LTspice simulation is shown below.
The clip voltage is provided by a TL431 2.5V accurate and stable reference IC, and the level can be adjusted from 2.5V to 0V by pot U4.
As can be seen, the output is clipped at 2.45V for the shown setting of the pot.
If you don't need an adjustable clip level, you can replace the pot with two fixed resistors.
View attachment 114745
BCX55B2V4 gives 2.35min / 2.4nom / 2.45max ( see pg 3 of Datasheet )
what are your thoughts about the one linked above in this thread that is set to clip at 2.4?For that wide a range, the Zener approach should work, if it's set to clip at about 2.25V.
It would be problematic.what are your thoughts about the one linked above in this thread that is set to clip at 2.4?
Likely a good guess.I'm guessing you never worked a GM.
I worked for their wire harness and terminal division, Packard Electric. And while I don't know about the electronics, I do know about them sending people from our plant to dealerships and distribution points to fix things that were a total mistake in design.Likely a good guess.
But I have.
But are you implying that GM's electronics are not designed to withstand voltage spikes on the 12V line?
If there weren't, they would likely be swamped by failures under warranty.
Thank you, you've come through again with some amazing help with my questions. I appreciate your input very much. Now i just have to find someone to build this circuit for me.It would be problematic.
Look at the clip from the data sheet below.
The maximum zener voltage is 2.45V which is near your upper limit.
And its high dynamic resistance and soft zener characteristics may cause an error in the voltage around 2V and below.
Add in the high temperature coefficient and you could exceed 2.49V at low temperatures.
View attachment 114758
How about this slightly more complicated circuit (2 added resistors) that gives much better performance.
Below is the LTspice simulation of a clip circuit using a TLV431 1.24V programmable shunt reference (Zener).
It gives a more accurate, stable, and sharper clip point.
The TLV431 clips when the Ref voltage (red trace) reaches 1.24V, as determined by the voltage divider consisting of R2 and R3 [giving an OUT2 clipping value (yellow trace) of 2.24V for the values shown].
Note the much poorer clip at OUT1 using a standard 2.5V zener (green trace).
(I didn't have the model for the 2.4V zener but the performance should be similar).
View attachment 114764
The circuit in post #27 is quite simple with only 4 components (3 resistors and the TLV431).Again, any and all ideas welcome on who could do it cost effectively.
The output from the sensor is likely ratiometric with the actual value of the 5V supply.
Your reference should then be a % (~50%) of the actual real time vallue of the 5V supply voltage and not absolute.
I need it to be packaged as small as possible, within reasonable cost, and with heat/moisture insulation... to some degree.
Typical automotive sensors are not 0-5V; Meaning you can;t really connect them to a DVM and convert to engineering units.I am not sure what your point is exactly, can you clarify further?