Download CMS Tracker Rod Pwr Line LP Filter

Rod Power Line Low-Pass Filter
Study
3 August 2004
Sam Burke
UCSB HEP Group
UCSB CMS Weekly Status Meeting
CMS Tracker Rod Filters Sam Burke EE
Slide 1
Progress
• Noise on CERN Rod Test System


Power line is source per battery tests
2.5 mV @ 1Mhz measured on Rod PS @UCSB
• Low Noise on UCSB Rod System

1 - 2 A/D Counts
UCSB CMS Weekly Status Meeting
CMS Tracker Rod Filters Sam Burke EE
Slide 2
Progress
• Inject Noise into UCSB system


introduce noise pulse train into 0.1 ohm resistor placed
at common power supply point and observe system
response.
Fixture currently being prepared for test
• Reduce self-induced noise with filtering


Place Low Pass Filter on power line
Shaper Noise Band Defined
– 1/260ns =4Mhz to 1/40ns =25Mhz
– >60dB attenuation in shaper band
UCSB CMS Weekly Status Meeting
CMS Tracker Rod Filters Sam Burke EE
Slide 3
Low Pass Filter Schematic
UCSB CMS Weekly Status Meeting
CMS Tracker Rod Filters Sam Burke EE
Slide 4
LP Filter Response
UCSB CMS Weekly Status Meeting
CMS Tracker Rod Filters Sam Burke EE
Slide 5
LP Filter Test Results
UCSB CMS Weekly Status Meeting
CMS Tracker Rod Filters Sam Burke EE
Slide 6
LP Filter
• Break 2 power
lines and common
line and insert
filter.
UCSB CMS Weekly Status Meeting
CMS Tracker Rod Filters Sam Burke EE
Slide 7
Open Filter Issues
• Voltage drop


Vgnd=IR=19A*4.9mohms=93mV on Gnd
V+2.5=IR=12A*4.9mohms=60mV on 2.5V line
• Heat Generation



I^2R=19^2*.0049ohms=1.7 watts on Gnd coil
I^2R=12^2*.0049=0.7 watts on 2.5V line coil
I^2R=7^2*.0049=0.24 watts on 1.25V line coil
• Core Saturation in Machines Magnetic Field


Open core may saturate in field
Investigate toriod candidate
UCSB CMS Weekly Status Meeting
CMS Tracker Rod Filters Sam Burke EE
Slide 8
Alternate Filter Approach
• Move filter outside of CMS magnetic enviornment


No saturation of filter inductors
Need to insert (splice) filter into Rod Power Cables
• Reduce heat generation by filter I^2 heating

Use lower winding resistance with a reduced noise
attenuation if acceptable
UCSB CMS Weekly Status Meeting
CMS Tracker Rod Filters Sam Burke EE
Slide 9
Alternate Inductor Impact
UCSB CMS Weekly Status Meeting
CMS Tracker Rod Filters Sam Burke EE
Slide 10
Rod LP Filter Prototype
• High Current
Inductors are on the
two DC Power
lines.
• Twisted pairs are
power sense lines
and analog sensor
lines
UCSB CMS Weekly Status Meeting
CMS Tracker Rod Filters Sam Burke EE
Slide 11
LP Filter At Rod Pwr Line
UCSB CMS Weekly Status Meeting
CMS Tracker Rod Filters Sam Burke EE
Slide 12
Pulse Transformer
UCSB CMS Weekly Status Meeting
CMS Tracker Rod Filters Sam Burke EE
Slide 13
Rod Module 1
• Top: Noise injection of 10
ns pulse, 30 mhz, 10vpk
• Bottom: Low Pass Filter
in Power Circuit
UCSB CMS Weekly Status Meeting
CMS Tracker Rod Filters Sam Burke EE
Slide 14
Rod Module 3 (under CCU)
• Top: Noise injection of 10
ns pulse, 30 mhz, 10vpk
• Bottom: Low Pass Filter
in Power Circuit
UCSB CMS Weekly Status Meeting
CMS Tracker Rod Filters Sam Burke EE
Slide 15
Rod Module 6
• Top: Noise injection of 10
ns pulse, 30 mhz, 10vpk
• Bottom: Low Pass Filter
in Power Circuit
UCSB CMS Weekly Status Meeting
CMS Tracker Rod Filters Sam Burke EE
Slide 16
Future Plans
UCSB CMS Weekly Status Meeting
CMS Tracker Rod Filters Sam Burke EE
Slide 17