Tracker meeting – July, 2006

TBS – TPSFE FM/FS tests

Lucio Accardo, INFN Perugia

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• All the 20 FM/FS TBS (Tracker Bias Supply) boards have been tested.

• Test procedure has been upgraded for the board functional test.

• The hardware equipment developed in Perugia and already used for QM2 tests was used.

• New software features have been implemented (automatic overcurrent control, text data file generation).

• Four linear regulators are implemented in the TBS. Each pair is independent from the other and is composed by two linear regulators in a cold redundant configuration.

• Each LR can be set at 80V or 60V.

• Each LR has its own over current protection, and the cold redundant LR switches ON in case the primary LR has low voltage output.

TBS - Introduction

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TBS - Test procedure

• Each of the four linear regulators has been tested with its nominal working load, in ON and OFF position, reading the voltages and the currents throughout the ADCs placed on board. • Each LR has been tested applying an over current to it; voltages and currents have been also read.

• Voltages between GRINGK and GNDK have been recorded. • Each register has been written and read into/from both the ACTELs, sending commands and reading back the board status.

• All the data (voltages, currents, registers’ values) have been written into a text file.

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TBS - Results

• 20 / 20 boards passed the functional tests.

• 95008 did not pass the first functional test: 110V instead of 80V (or 60V) has been measured on MVLR_1. After investigation, a bad resistor value (R112) was found; the board passed the functional test after reworking.

• 95011 did not pass the first functional test: 102V instead of 80V (or 60V) has been measured on MVLR_1; power consumption was 0.12A instead of 0.11A. After investigation a bad soldered diode (D58) was found; the board passed the functional test after reworking.

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• All the assembled 28 FM/FS TPSFE (Tracker Power Supply Front End) boards have been tested.

• The hardware equipment developed in Perugia and already used for QM2 tests was used.

• Test procedure and control software have been upgraded for the board functional test.

• 12 linear regulators are implemented in the TPSFE. Each one can generate the ±2V needed for the S and K front-end electronics.

• Each LR has an over current protection; if the over current persists, the circuit tries to keep the voltage ON for few milliseconds. In this case, a cycling signal is generated and is read from the Actel; after this signal cycles 16 times, the LR is automatically (if the AUTOMODE option is set) switched OFF from the Actel.

• TPSFE also controls and monitors the digital power of each half of 3 TDR2.

TPSFE - Introduction

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TPSFE - Test procedure

• Each linear regulator has been tested with its nominal working load, in ON and OFF position, reading the output voltages throughout the 6024E DAQ card from National Instruments. • Each LR has been tested applying an over current to it; voltages have been read and recorded.• The over current was applied for 4.1s, so that the LRs tried to switch ON itself for 16 times, letting the ACTEL switch it OFF. • TDR2 control and monitoring circuits have been also tested. • Each register has been written and read into/from both the ACTELs, sending commands and reading back the board status.• All the data (voltages, currents, registers’ values have been written into a text file).

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TPSFE – Results 1/2

• 27 / 28 boards passed the functional tests.

• A common error was found in the TDR2 monitoring circuits. During October last year, we found a bug on the values of 6 resistors; this information was sent to CSIST but, for some misunderstandings, it was not applied. All the boards have been reworked and checked.

• 95008 did not pass the first functional test: LRK0 over current counter was 0 for Actel A and B. The status signal was bad generated: R417 had wrong value; after reworking the board was OK.

• 95011 did not pass the first functional test: LRS1 over current protection did not work. R507 had a wrong value; after reworking the board was OK.

• 95023 did not pass the first functional test: Actel B – TDR_3 control signal did not work. R911 was broken; after reworking the board was OK.

• 95015 did not pass the first functional test: LRK0 over current protection did not work. Q65 was bad placed (unfortunately no pictures are available); after reworking the board was OK.

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TPSFE – Results 2/2

• 95007 did not pass the first functional test: Actel B did not answer to the slow control. It is a communication problem, because other features of the chip, like the AUTOMODE option, were working properly. I did not have time to investigate more on this board, and it will be done next time.

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Conclusions

• 47 boards are ready for conformal coating and ESS: CSIST will take care of this, because no functional tests are foreseen during ESS.

• I asked Mr.Wang for all the boards to be ready before next TEM (in October), together with the last 12 TPSFEs to be assembled. He said they are very busy now, but they’ll do the possible.

• About 15% of the boards had one assembly mistake; most of the components are automatically placed, and they will investigate on the reason of this high number of failures.