Hello everyone!
I´ve biult an instrumentation amplifier with 3 opamps, but the cmrr has been to low. I`ve increased it with bootstrapping the resistor of the input highpass.
Unfortunatelly I can`t calculate the function of the amp analytically, there are mistakes all the time. So I don`t know how to choose the values for high cmrr.
Please can anyone explain to me how I got the values of the resistors and capacitors? Maybe the function of voltage or Impedanz of 1 op-amp of the input-stage would be enough.
So the first schematic of the pdf is the instrumentation amplifier. I use C3 to bootstrapp R12 and C4 to b R13. With the bootstrapping I want to compensate the mismatch between the two input-high-passes!
Again, maybe it`s enough to explain the 2. schematic of the pdf.
best regards from germany (I´m sorry for the bad englisch)
Johannes
I´ve biult an instrumentation amplifier with 3 opamps, but the cmrr has been to low. I`ve increased it with bootstrapping the resistor of the input highpass.
Unfortunatelly I can`t calculate the function of the amp analytically, there are mistakes all the time. So I don`t know how to choose the values for high cmrr.
Please can anyone explain to me how I got the values of the resistors and capacitors? Maybe the function of voltage or Impedanz of 1 op-amp of the input-stage would be enough.
So the first schematic of the pdf is the instrumentation amplifier. I use C3 to bootstrapp R12 and C4 to b R13. With the bootstrapping I want to compensate the mismatch between the two input-high-passes!
Again, maybe it`s enough to explain the 2. schematic of the pdf.
best regards from germany (I´m sorry for the bad englisch)
Johannes
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