diff --git a/opamp_circuits_C_GARRETT/circuit2002_FIVEPOLE.png b/opamp_circuits_C_GARRETT/circuit2002_FIVEPOLE.png new file mode 100644 index 0000000..2577f17 Binary files /dev/null and b/opamp_circuits_C_GARRETT/circuit2002_FIVEPOLE.png differ diff --git a/opamp_circuits_C_GARRETT/circuit2002_LP1.png b/opamp_circuits_C_GARRETT/circuit2002_LP1.png new file mode 100644 index 0000000..f684897 Binary files /dev/null and b/opamp_circuits_C_GARRETT/circuit2002_LP1.png differ diff --git a/opamp_circuits_C_GARRETT/circuit2h.dia b/opamp_circuits_C_GARRETT/circuit2h.dia index 624df33..e9a6417 100644 Binary files a/opamp_circuits_C_GARRETT/circuit2h.dia and b/opamp_circuits_C_GARRETT/circuit2h.dia differ diff --git a/opamp_circuits_C_GARRETT/opamps.tex b/opamp_circuits_C_GARRETT/opamps.tex index 1a8106d..8514ca2 100644 --- a/opamp_circuits_C_GARRETT/opamps.tex +++ b/opamp_circuits_C_GARRETT/opamps.tex @@ -464,7 +464,7 @@ wihen it becomes a V2 follower). \centering \includegraphics[width=200pt]{./circuit2002.png} % circuit2002.png: 575x331 pixel, 72dpi, 20.28x11.68 cm, bb=0 0 575 331 - \caption{circuit2} + \caption{circuit 2} \label{fig:circuit2} \end{figure} @@ -478,6 +478,16 @@ The output of this is passed into another Sallen~Key filter (which although it m for its resistors/capacitors and thus a different frequency response) is idential from a failure mode perspective. Thus we can analyse the first Sallen~Key low pass filter and re-use the results. + +\begin{figure}[h] + \centering + \includegraphics[width=400pt,keepaspectratio=true]{./blockdiagramcircuit2.png} + % blockdiagramcircuit2.png: 689x83 pixel, 72dpi, 24.31x2.93 cm, bb=0 0 689 83 + \caption{Signal Flow though the five pole low pass filter} + \label{fig:blockdiagramcircuit2} +\end{figure} + + \paragraph{First Order Low Pass Filter.} We begin with the first order low pass filter formed by $R10$ and $C10$. % @@ -504,9 +514,11 @@ We will consider the latter type for this analysis. \hline FS1: R10 SHORT & & $No Filtering$ & & $LPnofilter$ \\ \hline FS2: R10 OPEN & & $No Signal$ & & $LPnosignal$ \\ \hline - FS3: C10 SHORT & & $No Signal$ & & $LPnosignal$ \\ \hline - FS4: C10 OPEN & & $No Filtering$ & & $LPnofilter$ \\ \hline + FS3: C10 SHORT & & $No Signal$ & & $LPnosignal$ \\ \hline + FS4: C10 OPEN & & $No Filtering$ & & $LPnofilter$ \\ \hline + \hline + \end{tabular} \end{table} @@ -527,17 +539,17 @@ from the $FirstOrderLP$ and the OPAMP component. \centering % used for centering table \begin{tabular}{||l|c|c|l|l||} \hline \hline - \textbf{Test} & \textbf{Amplifier} & \textbf{ } & \textbf{General} \\ + \textbf{Test} & \textbf{Circuit} & \textbf{ } & \textbf{General} \\ \textbf{Case} & \textbf{Effect} & \textbf{ } & \textbf{Symptom Description} \\ % R & wire & res + & res - & description \hline \hline TC1: $OPAMP$ LatchUP & Output High & & LP1High \\ - TC2: $OPAMP$ LatchDown & Output Low & & LP1Low \\ \hline + TC2: $OPAMP$ LatchDown & Output Low & & LP1Low \\ TC3: $OPAMP$ No Operation & Output Low & & LP1Low \\ - TC4: $OPAMP$ Low Slew & Unwanted Low pass filtering & & LP1ExtraLowPass \\ \hline - TC5: $LPnofilter $ & No low pass filtering & & LP1NoLowPass \\ \hline - TC6: $LPnosignal $ & No input signal & & LP1low \\ + TC4: $OPAMP$ Low Slew & Unwanted Low pass filtering & & LP1filterincorrect \\ \hline + TC5: $LPnofilter $ & No low pass filtering & & LP1filterincorrect \\ + TC6: $LPnosignal $ & No input signal & & LP1nosignal \\ \hline \hline \hline @@ -549,7 +561,20 @@ From the table~\ref{tbl:firststage} we can see three symptoms of failure of the first stage of this circuit (i.e. R10,C10,IC1). We can create a derived component for it, lets call it $LP1$. -$$ fm(LP1) = \{ LP1High, LP1Low, LP1ExtraLowPass, LP1NoLowPass \} $$ +$$ fm(LP1) = \{ LP1High, LP1Low, LP1filterincorrect, LP1nosignal \} $$ + + +In terms terms of the circuit we have modelled the functional groups $FirstOrderLP$, and +$LP1$. We can represent these on the circuit diagram by drawing contours around the components +on the schematic as in figure~\ref{fig:circuit2002_LP1}. + +\begin{figure}[h] + \centering + \includegraphics[width=200pt,keepaspectratio=true]{./circuit2002_LP1.png} + % circuit2002_LP1.png: 575x331 pixel, 72dpi, 20.28x11.68 cm, bb=0 0 575 331 + \caption{Circuit showing functional groups modelled so far.} + \label{fig:circuit2002_LP1} +\end{figure} \paragraph{Second order Sallen Key Low Pass Filter.} @@ -562,27 +587,30 @@ We can analyse one and re-use the results for the second. \centering % used for centering table \begin{tabular}{||l|c|c|l|l||} \hline \hline - \textbf{Test} & \textbf{Amplifier} & \textbf{ } & \textbf{General} \\ + \textbf{Test} & \textbf{Circuit} & \textbf{ } & \textbf{General} \\ \textbf{Case} & \textbf{Effect} & \textbf{ } & \textbf{Symptom Description} \\ % R & wire & res + & res - & description \hline \hline TC1: $OPAMP$ LatchUP & Output High & & SKLPHigh \\ - TC2: $OPAMP$ LatchDown & Output Low & & SKLPLow \\ \hline + TC2: $OPAMP$ LatchDown & Output Low & & SKLPLow \\ TC3: $OPAMP$ No Operation & Output Low & & SKLPLow \\ - TC4: $OPAMP$ Low Slew & Unwanted Low pass filtering & & SKLPIncorrect \\ \hline - TC5: $R1 OPEN$ & No input signal & & SKLPIncorrect \\ \hline - TC6: $R1 SHORT$ & incorrect low pass filtering & & SKLPIncorrect \\ - TC7: $R2 OPEN$ & No input signal & & SKLPnosignal \\ \hline - TC8: $R2 SHORT$ & incorrect low pass filtering & & SKLPIncorrect \\ - TC9: $C1 OPEN$ & reduced/incorrect low pass filtering & & SKLPIncorrect\\ \hline - TC10: $C1 SHORT$ & reduced/incorrect low pass filtering & & SKLPIncorrect \\ - TC11: $C2 OPEN$ & reduced/incorrect low pass filtering & & SKLPIncorrect \\ \hline - TC12: $C2 SHORT$ & No input signal, low signal & & SKLPnosignal \\ + TC4: $OPAMP$ Low Slew & Unwanted Low pass filtering & & SKLPfilterIncorrect \\ \hline + TC5: R1 OPEN & No input signal & & SKLPfilterIncorrect \\ + TC6: R1 SHORT & incorrect low pass filtering & & SKLPfilterIncorrect \\ \hline + + TC7: R2 OPEN & No input signal & & SKLPnosignal \\ + TC8: R2 SHORT & incorrect low pass filtering & & SKLPfilterIncorrect \\ \hline + + TC9: C1 OPEN & reduced/incorrect low pass filtering & & SKLPfilterIncorrect\\ + TC10: C1 SHORT & reduced/incorrect low pass filtering & & SKLPfilterIncorrect \\ \hline + + TC11: C2 OPEN & reduced/incorrect low pass filtering & & SKLPfilterIncorrect \\ + TC12: C2 SHORT & No input signal, low signal & & SKLPnosignal \\ \hline \hline \hline \end{tabular} -\label{tbl:firststage} +\label{tbl:sallenkeylp} \end{table} We now can create a derived component to represent the Sallen Key low pass filter, which we can call $SKLP$. @@ -593,29 +621,32 @@ $$ fm ( SKLP ) = \{ SKLPHigh, SKLPLow, SKLPIncorrect, SKLPnosignal \} $$ \paragraph{A failure mode model of Op-Amp Circuit 2.} -We now have {\dcs} representing the three stages of this filter. -We represent this as a block diagram to represent the signal flow, in figure~\ref{fig:blockdiagramcircuit2}. +We now have {\dcs} representing the three stages of this filter +and this follows the signal flow in the filter circuit (see figure~\ref{fig:blockdiagramcircuit2}). -\begin{figure}[h] - \centering - \includegraphics[width=400pt,keepaspectratio=true]{./blockdiagramcircuit2.png} - % blockdiagramcircuit2.png: 689x83 pixel, 72dpi, 24.31x2.93 cm, bb=0 0 689 83 - \caption{Signal Flow though five pole low pass filter} - \label{fig:blockdiagramcircuit2} -\end{figure} - As the signal has to pass though each block/stage in order to be `five~pole' filtered, we need to bring these three blocks together into a {\fg} in order to get a failure mode model for the whole circuit. +We can index the Sallen Key stages, and these are marked on the ciruit schematic in figure~\ref{fig:circuit2002_FIVEPOLE}. + +\begin{figure}[h]+ + \centering + \includegraphics[width=200pt]{./circuit2002_FIVEPOLE.png} + % circuit2002_FIVEPOLE.png: 575x331 pixel, 72dpi, 20.28x11.68 cm, bb=0 0 575 331 + \caption{Functional Groups in Five Pole Low Pass Filter on schematic} + \label{fig:circuit2002_FIVEPOLE} +\end{figure} + +\pagebreak[4] + +So our final {\fg} will consist of the derived components $\{ LP1, SKLP_1, SKLP_2 \}$. +We represent the desired FMMD hierarchy in figure~\ref{fig:circuit2h}. -We can represent the desired FMMD hierarchy in figure~\ref{fig:circuit2h}. - - -\begin{figure}[h] +\begin{figure}[h]+ \centering \includegraphics[width=300pt]{./circuit2h.png} % circuit2h.png: 676x603 pixel, 72dpi, 23.85x21.27 cm, bb=0 0 676 603 @@ -623,9 +654,82 @@ We can represent the desired FMMD hierarchy in figure~\ref{fig:circuit2h}. \label{fig:circuit2h} \end{figure} +%\pagebreak[4] + + + + + + + +%$$ fm ( SKLP ) = \{ SKLPHigh, SKLPLow, SKLPIncorrect, SKLPnosignal \} $$ +%$$ fm(LP1) = \{ LP1High, LP1Low, LP1ExtraLowPass, LP1NoLowPass \} $$ + +\begin{table}[ht]+ +\caption{Five Pole Low Pass Filter: Failure Mode Effects Analysis: Single Faults} % title of Table +\centering % used for centering table +\begin{tabular}{||l|c|l|l|l||} +\hline \hline + \textbf{Test} & \textbf{Circuit} & \textbf{ } & \textbf{General} \\ + \textbf{Case} & \textbf{Effect} & \textbf{ } & \textbf{Symptom Description} \\ +% R & wire & res + & res - & description +\hline +\hline + TC1: $LP1$ LP1High & signal HIGH & & HIGH \\ + TC2: $LP1$ SKLPLow & signal LOW & & LOW \\ + TC3: $LP1$ LP1filterIncorrect & filtering incorrect & & FilterIncorrect \\ + TC4: $LP1$ LP1nosignal & no signal propogated & & NO\_SIGNAL \\ \hline + + + + TC5: $SKLP_1$ High & signal HIGH & & HIGH \\ + TC6: $SKLP_1$ Low & signal LOW & & LOW \\ + TC7: $SKLP_1$ filterIncorrect & filtering incorrect & & FilterIncorrect \\ + TC8: $SKLP_1$ nosignal & no signal propogated & & NO\_SIGNAL \\ \hline + + + TC9: $SKLP_2$ High & signal HIGH & & HIGH \\ + TC10: $SKLP_2$ Low & signal LOW & & LOW \\ + TC11: $SKLP_2$ filterIncorrect & filtering incorrect & & FilterIncorrect \\ + TC12: $SKLP_2$ nosignal & no signal propogated & & NO\_SIGNAL \\ \hline + + \hline +\hline +\end{tabular} +\label{tbl:fivepole} +\end{table} + + + + + +We now can create a {\dc} to represent the circuit in figure~\ref{fig:circuit2}, we can call it +$FivePoleLP$ and applying the $fm$ function to it (see table~\ref{tbl:fivepole}) yields $fm(FivePoleLP) = \{ HIGH, LOW, FilterIncorrect, NO\_SIGNAL \}$. + + +\pagebreak[4] + +The failure modes for the low pass filters are very similar, and the propogation of the signal +is simple (as it is never inverted). The circuit under analysis is -- as shown in the block diagram (see figure~\ref{fig:blockdiagramcircuit2}) -- +three opamp driven non-inverting low pass filter elements; It is not suprising therefore that they have very similar failure modes. +From a safety point of view, the failure modes $LOW$, $HIGH$ and $NO\_SIGNAL$ +could be easily detected; the failure symptom $FilterIncorrect$ may be less observable. + + + + + + + + + + + + + + + -So out final {\fg} will consist of the derived components -$\{ LP1, SKLP_1, SKLP_2 \}$. \clearpage \section{Op-Amp circuit 3} @@ -637,12 +741,9 @@ $\{ LP1, SKLP_1, SKLP_2 \}$. \caption{Circuit 3} \label{fig:circuit3} \end{figure} -\end{tabular} -\label{ampfmea} -\end{table} -\clearpage -\section{Standard Non-inverting OP AMP} +%\clearpage +%\section{Standard Non-inverting OP AMP} \clearpage @@ -662,7 +763,7 @@ $\{ LP1, SKLP_1, SKLP_2 \}$. \paragraph{ Creating a fault hierarchy.} The main concept of FMMD is to build a hierarchy of failure behaviour from the {\bc} level up to the top, or system level, with analysis stages between each -transition to a higher level in the hierarchy. +transition to a higher level in the hierarchy. $$ fm(LP1) = \{ LP1High, LP1Low, LP1ExtraLowPass, LP1NoLowPass \} $$ The first stage is to choose {\bcs} that interact and naturally form {\fgs}. The initial {\fgs} are collections of base components. @@ -846,7 +947,7 @@ they always have a small number of system failure modes. Idea stage on this section \begin{itemize} - \item Look at OPAMP circuits + \item Look at OPAMP circuits, pick one (say $\mu$741) \item examine number of components and failure modes \item outline a proposed FMMD analysis \item Show FMD-91 OPAMP failure modes -- compare with FMMD