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| -0.7V rail creation for op amp |
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| exe:
Afaik, there was an IC that generated -0.2V across its leads. It was connected in between ground negative supply of the opamp. I can't find it. I saw it in old app notes. But the more I think about it the less I'm sure it's possible to create such a two-terminal device (unless it's a battery). May be I'm dreaming. |
| ogden:
--- Quote from: exe on January 11, 2019, 02:01:25 pm ---Afaik, there was an IC that generated -0.2V across its leads. It was connected in between ground negative supply of the opamp. I can't find it. --- End quote --- I did mention such already: --- Quote from: ogden on January 10, 2019, 07:21:05 pm ---You may consider purpose-built negative bias IC like http://www.ti.com/product/LM7705 --- End quote --- |
| David Hess:
--- Quote from: duak on January 11, 2019, 01:17:10 am ---Blueskull, is the 2N3055 trick the one where the base-emitter junction is reverse biased to breakdown, but a small negative voltage relative to the emitter appears on the collector? --- End quote --- I am sure it is. I did it with 2N3904s and while it works, optocouplers provide at least 10 times the efficiency. |
| TrickyNekro:
Does your ADC have a -Vref? Cause if yes you can bias the -Vref with a simple diode and resistor. Granted you lose a bit of voltage range but that can be accounted for. |
| Hiemal:
As an alternative you can use a 555 timer as a charge pump to create a negative voltage. |
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