From: Jan Michel Date: Mon, 29 Jul 2013 14:35:06 +0000 (+0200) Subject: more comments about flex cable and power supply X-Git-Url: https://jspc29.x-matter.uni-frankfurt.de/git/?a=commitdiff_plain;h=ad845dda33fae310986f9c1c81bb4ce061562c08;p=mvd_docu.git more comments about flex cable and power supply --- diff --git a/electronics/electronics2013.pdf b/electronics/electronics2013.pdf index e945aa0..828da90 100644 Binary files a/electronics/electronics2013.pdf and b/electronics/electronics2013.pdf differ diff --git a/electronics/electronics2013.tex b/electronics/electronics2013.tex index efc3b85..ce86dce 100644 --- a/electronics/electronics2013.tex +++ b/electronics/electronics2013.tex @@ -20,7 +20,7 @@ \begin{center} \includegraphics[width=.8\textwidth]{./boardchain.png} \end{center} -\caption{The setup of the new read-out board chain between sensor and read-out controller. Redish, +\caption{The setup of the new read-out board chain between sensor and read-out controller. Reddish, Bluish and Yellowish colors show the origin of components.} \end{figure} @@ -50,8 +50,8 @@ length. \final{The final setup will most likely use different cables with better improved handling.} Cables as well as connectors will be bought by GSI. Table \ref{iocount} gives a rough count of necessary I/O. The final number of connections required -will strongly depend on the realisation of the converter board, mainly with respect to the data -busses for switches and ADCs. A.t.m. there are 14 I/O per converter board plus 12 I/O per sensor. +will strongly depend on the realization of the converter board, mainly with respect to the data +buses for switches and ADCs. A.t.m. there are 14 I/O per converter board plus 12 I/O per sensor. Note that this setup is for M26 sensors only where we will not have any ladders larger than 2 sensors. The number of I/O for the final sensor will be different. @@ -71,7 +71,7 @@ Voltage and JTAG switch (Bus) & 0 & 4 (4) & 0 & 1 (1) \\ Total & 1 & 13 (6) & 10 & 2 (2)\\ \end{tabularx} \caption{Inputs/Outputs from the FPGA to the converter board. The number in -parantheses shows the number of I/O that could be replaced by a non-differential connection.} +parentheses shows the number of I/O that could be replaced by a non-differential connection.} \label{iocount} \end{table} @@ -109,7 +109,7 @@ ADC are used, the remaining channel can be connected to the ground sense wire. The on-board ADC should provide about 1 MSPS and a SPI (or similar) interface. AD7928 is a possible candidate for single ended measurement. -(I do not have a differential ADC in mind yet, but the ADC implemented in Attiny microcontrollers +(I do not have a differential ADC in mind yet, but the ADC implemented in ATtiny micro-controllers does fit the requirements despite conversion speed.) @@ -144,13 +144,26 @@ All signals from and to the sensor should be fed through LVDS buffers to reduce sensors' output drivers and to improve signal quality. -\subsection{Test Features} +\subsection{Power Supply} +The CB needs to generate three voltages for each sensor. They should be independent on the board, +but as a test feature, one block should be able to serve both connected sensors. That is, provide +jumpers to bridge power supplies of both sensors to test running several sensors in parallel on all +three voltages. + +Estimated power consumption of the converter board (per sensor): \begin{itemize*} - \item The final setup will profit if the number of voltage regulators is reduced. We should -prepare a test to run several sensors in parallel on one supply. That is, provide jumpers to bridge -power supplies of both sensors to test running several sensors in parallel on all three voltages. + \item VDD Analog: 3.3~V, 0~mA + \item VDD Digital: 3.3~V, 0~mA + \item V Clamping: $\approx$ 0~V, 2~mA + \item VCC Board: 3.3~V, t.b.d.~mA \end{itemize*} +To improve the noise environment and the stability of voltages, linear regulators can be used. +Using a supply voltage of e.g. 4~V for the CB would result in an estimated 0.5~W higher power loss +on the board as compared to switching converters. This seems acceptable since cooling with fans +will be possible (if needed) even in the final set-up with many sensors. + + \subsection{Components} @@ -159,18 +172,49 @@ power supplies of both sensors to test running several sensors in parallel on al current, smaller form factor), e.g. BLM41 and similar. \end{itemize*} +\clearpage \section{Cable CB to FEB} -First iteration: Reuse old flex cables, two old cables should provide enough connections to the -front-end board, also with respect to the number of additional monitoring signals needed. +First iteration: Reuse old flex cables. The estimation in table \ref{CbFebCable} shows that the +scheme uses 35 wires per sensor plus four per FEB. In total 74 wires for one 2-sensor FEB board. +Two old cables should provide enough connections to the front-end board. +\final{Sense lines for VDiscr might be removed for the final version and replaced by test pads on +the FEB for measurement during commissioning.} Later, a new cable can be developed taking into account that it will be fully placed outside the acceptance of the detector. I.e. a two-layer cable with broad ground and power planes should provide a much cleaner voltage for the sensor. One important fact is that this cable has to be fed -into the vacuum vessel. The total length of the cable must at least 50 cm in the final version. +into the vacuum vessel. \final{The total length of the cable must at least 50 cm in the final +version.} + +The pin-out on the FEB should be slightly changed, at least an additional sense line for ground up +to the sensor is needed. -The pin-out on the FEB should be slighly changed, at least a additional sense line for ground up to -the sensor is needed. Using sense lines for the supply voltages would be nice but is most liekly -not viable with the current bonding / cable set-up. + +\begin{table}[htb] + \centering +\begin{tabular}{l|c|c|c|c} + & \multicolumn{2}{c|}{\textbf{per Sensor}} & \multicolumn{2}{c}{\textbf{per +FEB}} \\ +\textbf{Purpose} & \textbf{Single} & \textbf{Differ.} & \textbf{Single} & \textbf{Differ.}\\ +\hline +Sensor Data & - & 4 & - & -\\ +Sensor Control & - & 1 & 2 & - \\ +JTAG & 2 & - & 2 & - \\ +Temperature & 1 & - & - & - \\ +Analog VCC & \discuss{2} & - & - & - \\ +Analog GND & \discuss{5} & - & - & - \\ +Clamping VCC & 1 & - & - & - \\ +Digital VCC & \discuss{1} & - & - & - \\ +Digital GND & \discuss{2} & - & - & - \\ +Sense VCC & 2 & - & - & - \\ +Sense GND & 1 & - & - & - \\ +Sense VDiscr & 8 & - & - & - \\ +\hline +Total & 25 & 5 & 4 & 1 \\ +\end{tabular} +\caption{Connections between CB and FEB.} +\label{CbFebCable} +\end{table} \clearpage \section{Front-end Board (FEB)} @@ -179,8 +223,9 @@ short sides and with an additional broad connector on the side towards the CB. \subsection{Jtag} The switches for bridging of sensors will be located on the CB as before, so no active -components are necessary for Jtag. -\discuss{Termination might be foreseen if necessary}. +components are necessary for Jtag. \discuss{Termination might be foreseen if necessary}. Using +differential signaling between CB and FEB would be nice although active components would be +required on the FEB to convert the signal back to single ended. \subsection{Data} @@ -199,5 +244,9 @@ final board and there is no harm if such a circuit fails. There is no need to develop a new sensor flex print cable at the current stage. The final length of this cable is likely to be about 15 cm. +The pin-out of the connector on the FEB has to be changed to allow for an additional GND sense line. +Using sense lines for the supply voltages would be nice but is most likely +not viable with the current bonding / cable set-up. + \end{document}