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And now for something completely different

And now for something completely different. First results from the DC-DC Stavelet Peter & Ashley w ith Giulio & John. DC-DC Stavelet First Module. Unstuck?. SE4445 is used to attach modules to stavelets . At room temperature, this takes a long time to cure. When the module was

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And now for something completely different

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  1. And now for something completely different First results from the DC-DC Stavelet Peter & Ashley with Giulio & John

  2. DC-DC Stavelet First Module

  3. Unstuck? • SE4445 is used to attach modules to • stavelets. At room temperature, this takes • a long time to cure. When the module was • first powered, it bowed as shown. It’s not • quite as bad now, but it does still bow. • Do we need to remove and re-attach this module or is it OK to leave it? • If we use SE4445 for further modules, do we need to allow a longer cure before application of power? Power OFF H1 H0 Power ON Power ON

  4. Chip & Strip Numbers 32 33 34 35 36 37 38 39 40 41 Channel 0 Channel 1279 DC-DC Edge BCC Edge 64 65 66 67 68 69 70 71 72 73 Strictly, the hardware channel numbering is contiguous only for the upper column. Chip 64 for example has channel 127 at the sensor edge – but in all plots which follow this has been corrected in software to match the above labels.

  5. Shield Connections (IN USE) Shield Referencing Shield Connection (NOT IN USE) Option to Link LVDS & Sensor Shields Backplane Connection (H1 only)

  6. ENC Measurements Ch 0 -> by BCC Ch 1279 -> by DC-DC H0 Unpowered H1 Original Shield H0 Original Shield H1 Unpowered H0 Original Shield H1 Original Shield Both hybrids at Once H0 Outer Column H0 Inner Column H1 Inner Column H1 Outer Column 10/06/2011, 10V 3.0A limit, H0 DC referenced to shield, H1 AC referenced to shield

  7. ENC Measurements Ch 0 -> by BCC Ch 1279 -> by DC-DC H0 Unpowered H1 Wrapped Shield H0 Wrapped Shield H1 Unpowered H0 Wrapped Shield H1 Wrapped Shield Both hybrids at Once 10/06/2011, 10V 3.5A limit, H0 DC referenced to shield, H1 AC referenced to shield

  8. Cursory investigation of B fieldalong axis through converter centres Converter PCB now closer to the hybrid edge than for the single module DC-DC tests (~2mm from ~7mm) and it’s also now in the same plane. Therefore the scope for pickup is increased. cm 5 0 10

  9. HMS3000 Typical Screenshot Shields wrapped in Cu tape, both converters running, 3cm point

  10. Shields Removedboth converters running cm Noise Floor dBm Not Calibrated: relative measurement only

  11. Shields Removed H0 converter running, H1 powered down cm Noise Floor dBm Not Calibrated: relative measurement only

  12. Shields Removed H0 powered down, H1 converter running cm Noise Floor dBm Not Calibrated: relative measurement only

  13. Shields Wrapped in Copper Tapeboth converters running cm Noise Floor dBm Not Calibrated: relative measurement only

  14. Shields Wrapped in Copper TapeH0 converter running, H1 powered down cm Noise Floor dBm Not Calibrated: relative measurement only

  15. Shields Wrapped in Copper TapeH0 powered down, H1 converter running cm Noise Floor dBm Not Calibrated: relative measurement only

  16. Field leaks through gap between shield and converter PCB H1 Will a “skirt” help? fitted over existing layer of copper tape H0 Also revised hybrid referencing to make both DC referenced

  17. Effect of “Skirt” on B field WITHOUT SKIRT WITH SKIRT These measurements were made using the smallest magnetic field probe placed immediately adjacent to the converter shield of hybrid H0 of the single DC-DC module M5 (not stavelet module M13).

  18. H0 Wrapped + Skirt H1 Wrapped Shield One hybrid at a time H0 Wrapped + Skirt H1 Wrapped Shield Both hybrids at Once H0 Wrapped Shield H1 Wrapped Shield One hybrid at a time H0 Wrapped Shield H1 Wrapped Shield Both hybrids at Once 21/06/2011, 10V 5.0A limit, Both hybrids DC referenced

  19. H0 Original H1 Wrapped Shield One hybrid at a time H0 Original Shield H1 Wrapped Shield Both hybrids at Once H0 Wrapped Shield H1 Wrapped Shield One hybrid at a time H0 Wrapped Shield H1 Wrapped Shield Both hybrids at Once 21/06/2011, 10V 5.0A limit, Both hybrids DC referenced

  20. TEST 4: 5.0A Wrapped Shields Both hybrids at Once TEST 3: 3.0A Wrapped Shields Both hybrids at Once TEST 2: 3.5A Wrapped Shields Both hybrids at Once TEST 1: 5.0A Wrapped Shields Both hybrids at Once 22/06/2011, 10V variable current limit, Both hybrids DC referenced

  21. TEST 4: 21/06/2011 Sensor Shield DC @ both edges Each hybrid separately TEST 3: 21/06/2011 Sensor Shield DC @ both edges Both hybrids at Once TEST 2: 21/06/2011 Sensor Shield DC @ BCC edge Each hybrid separately TEST 1: 21/06/11 Sensor Shield DC @ BCC edge Both hybrids at Once Wrapped shields used throughout, TTi supply at 10V 5A limit

  22. Double Trigger Noise @ 0.75fC TTi TSX3510P @ 10V, wrapped shields, both hybrids at once (yes it really is this clean)

  23. Double Trigger Noise @ 0.50fC TTi TSX 3510P @ 10V, wrapped shields, both hybrids at once

  24. Summary • Increasing the TTi TSX3510P PSU current limit above 3.0A has no effect upon the ENC noise • Avoid values below this • supply will not trip but may current limit • Referencing changes have had a greater effect than increasing the mass of the shields • Extra 2 bonds per hybrid at DC-DC edge helped reduce the noise • Beyond that, all that’s present in the design is the option to connect the sensor shield pad to the LVDS shield. • Next : further reduce inductance of the shield connection • How can we improvise Cu or Al foil connections between Al shield and adjacent DC-DC power return line? • See over for first attempt....

  25. Lowering the Inductance of the Shield Connection Remove kapton tape from power bus Partially remove kapton cover from sensor shield Add a dozen bonds to connect them together => Sensor Shield is connected directly to power GND

  26. TEST 5: 30/06/2011 Sensor Shield DC & to power Return Each hybrid separately NEW TEST 5: 29/06/2011 Sensor Shield DC & to power return Both hybrids at Once TEST 4: 21/06/2011 Sensor Shield DC @ both edges Each hybrid separately TEST 3: 21/06/2011 Sensor Shield DC @ both edges Both hybrids at Once Wrapped shields used throughout, TTi supply at 10V 5A limit

  27. Future Plans Continue to lower the inductance of the shield connection What if this does not work? ????

  28. Backup

  29. Naked Converters! Converter 06: BC0000000476043A Converter 14: 7C0000000455D23A Q) Does the precise physical orientation of each coil have any great significance?

  30. M13 Stavelet Best running one at a time Wrapped Shields M13 Single Module Result (SP @ Liverpool) M13 Stavelet Best running both at once Wrapped Shields

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