CMS ECAL Powering CMS ECAL Powering What Have we Learned from the Commercial Buck What Have we Learned from the Commercial Buck Converters? Converters? S. Dhawan, O. Baker, H. Chen R. Khanna, J. Kierstead, D. Lynn, A. Mincer , A. Musso S. Rescia, H. Smith, P. Tipton, M. Weber Abstract Abstract Commercial power converters that have voltage ratios greater than ten and are capable of running near the LHC collision region would increase the efficiency of the power distribution system of the ATLAS Silicon Tracker high luminosity upgrade. The devices must operate in a high magnetic field (2 T) and be radiation hard to ~50-100 Mrad and ~10 15 N eq /cm 2 . These converters are to be mounted on the same multi-chip modules as the ASIC readout chips or in close vicinity without introducing any additional readout noise due to the high switching frequencies. Such devices will permit higher voltage power delivery to the tracker and thus increase overall power efficiency by limiting the ohmic losses in the stretch of cable (about 100 meters) between the tracker and the power sources. Satish.Dhawan@yale. edu Power Distribution Schemes and Efficiencies 10:1 Voltage Ratio Converter 10:1 Voltage Ratio Converter Need for New methods of Power Need for New methods of Power Distribution Distribution Presently LHC inner detector electronics use DC power supplies located in the counting house that feed low voltage power over a long distance (30 m for CMS and 140 m for ATLAS detector). Here we focus on the powering of the silicon tracker for the high luminosity LHC that shall result in x10 higher luminosity and use x10 more detecting elements. The “Power Delivery with Existing SCT Cables” plot illustrates the problem. At present 10.25 V power from the counting house is delivered by 4088 power cables each with a resistance of 4.5 Ω. The 10 chip ASIC readout chip hybrid Kapton PCB needs 1.5 amps @ 3.5 Volts. The bar graph shows the power delivery efficiency of ~33%. In an upgraded ASIC design with finer lithography and x2 more chips, the voltage drops to 1.3 V and with the same cables the power delivery efficiency drops to 10%. By inserting a DC-DC with x10 voltage converter on the 20 chip hybrid Kapton PCB, the efficiency climbs to over 80%. 2008 Radiation Damage Tests 2008 Radiation Damage Tests There is a clear need for a new system of power delivery to the upgraded Atlas Silicon Tracker for the SLHC. Conventional powering will result in an efficiency of power delivery to the detector of about 10% with existing cables whose size are limited in cross section due to space and mass constraints. A system featuring DC-DC converters with voltage ratios of ten will result in an estimated efficiency on the order of 70-80% with existing cables. One approach to DC-DC conversion utilizes the buck regulator architecture. As DC-DC buck converters are commonly used in the commercial market, we have been surveying and testing currently available devices to understand the present state of the art. Yale University, Brookhaven National Laboratory, National Semiconductor Corp, Rutherford Appleton Laboratory, New York University & Rutherford Appleton Laboratory Device Time in Seconds Dose before Damage Seen (krad) Observations Damage Mode TPS 62110 720 40 Increasing input current ISL 8502 730 40.6 Increasing input current MAX 8654 850 47.2 Loss of output voltage regulation ADP 21xx 1000 55.6 Loss of output voltage regulation ST 1S10 2250 125 Loss of output voltage regulation IR3822 2500 139 Increasing input current EN5382 2000 111 Loss of output voltage regulation EN5360 #3 864000 48 Mrad MINIMAL DAMAGE EN5360 #2 TESTED IN 2007 100 Mrad MINIMAL DAMAGE Enpirion: Enpirion: In our radiation testing Enpirion device EN5360 has outlasted all other irradiated devices from all manufacturers, while the similar EN5365 and EN5382 failed. The EN5360 was made by IHP Microelectronics foundry in Germany while successor devices are fabricated by Dongbu HiTek semiconductor in South Korea. Both are on 0.25 m CMOS process, but some differences in the foundry processes and perhaps in the device circuit design make the EN5360 radiation hard. Recently Los Alamos National Laboratory irradiated an EN5360 and its successor EN5365 with heavy ions and protons for space satellite use. Their conclusion is that while both are suitable for their purposes, the EN5360 showed no effect up to their proton dosage limit while EN5365 failed. Enpirion EN5360 is a proof of principle that a commercial COTS device can be radiation hard. In our visit to the HP factory in Nov 2008, it was revealed that they have developed 12 Volt FET transistors in the same process. This is essential for a 10:1 Voltage conversion BUCK. Samples of these transistors have been irradiated to levels exceeding those expected at the SLHC. We are attempting to understand differences in the IHP fabrication process that lead to a successful device. Additionally, as next generation devices come on the market we will use the infrastructure we developed Conclusions/ Future Work Conclusions/ Future Work Air Coils Proximity Effect increases Losses 4088 Cables 10 Chip Hybrid – SCT Module for LHC Counting House 3.5 V 20 Chip Hybrid – Si Tr Module for Hi Luminosity Cable Resistance = 4.5 Ohms 1.5 amps 2.4 amps 20 Chip Hybrid – Si Tr Module for Hi Luminosity 1.3 V 1.3 V 2.4 amps 10.25 V 12.1V 14.08 V 13 V Voltage Drop = 6.75 V Voltage Drop = 10.8V 0.24 amps Voltage Drop = 1.08 V Length of Power Cables = 140 Meters Pow erD elivery w ith Existing SC T C ables (total= 4088) R esistance = 4.5 O hm s 0 10 20 30 40 50 60 70 80 90 100 3.5 V @ 1.5 am ps 1.3 V @ 2.4 am ps 1.3 V @ 2.4 am ps with x10 B uck switcher. Efficiency 90% V oltage @ Load Pow erEfficiency % Efficiency Efficiency (%) Output Current (amps) Enpirion 5360 before and after radiation, Vin = 5.5V Note – Device #2 Survived Previous Radiation Run #3 Aug-4- 2008 #2 Aug-4- 2008 #3 Aug-29-2008 #1 Aug-4- 2008 0 10 20 30 40 50 60 70 80 90 100 0 0.5 4.5 3.5 2.5 1.5 1.0 2.0 3.0 4.0 X 10 DC-DC Power Converte r 1 CMS Trigger Tower CMS 32.K Trigger Towers = 50 K amps ENB LDO 1.2V CMS 32.K Trigger Towers = 50,000 amps 12V 10:1 Buck Converter 5 V Low Cost: An ASIC + Inductor + Caps 10:1 Voltage Ratio @ 1 MHz High Side switch on for 100 nsec Low Side switch on for 900 nsec High Speed CMOS Switching Processor Switching Losses – High Side Conduction Losses – Low Side In Future speed increase to 20 MHz B uck R egulatorEfficiency after100 M rad dosage 0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00 0.000 1.000 2.000 3.000 4.000 5.000 6.000 O utputCurrentAm ps P ow erEfficiency A fter E xposure B efore E xposure February 2007 Tests Done in 2007 Radiation Test – Enpirion 6 amp Device 0.25 µm CMOS – 100 Mega rads Evaluation Boards: Enpirion, Linear Technology, Micrel, MPS, TI etc Air Coil Tests on Chips with External Inductors Pick up Noise: RHIC Polarimeter Silicon with Analog Readout RF Leakage Noise and Pickup Tests - ATLAS Silicon Tracker Module at RAL Magnetic Field Vout increased 1in 900 @ 7T Load Efficiency Tests Noise Same PCB Tests: DC-DC Converter on the Hybrid @ BNL & Yale Antenna Effect Tests After 100 M rads Before Si Sensor 8x10 cms Si Sensor 8x10 cms Buck 7 Tesla Superconducting Magnet: Persistent Mode Tests Done in 2008 Radiation Test – A dozen devices- Why are Enpirion chips (IHP Foundry) Rad Hard ? Combination of Foundry & Circuit Design Discuss with IHP, Chip Designers, etc Air Coil Developments Load Efficiency Tests for 10:1 Voltage Conversion ratio Features inside a Buck Chip Power Down: Low power mode. Shut output switches Output High side current limit pulse by pulse (turn off high side FET. After 16 times go to soft Start) Output Low side current limit pulse by pulse (turn off low side FET) Power OK if Vout with in 10% of set voltage Vout overvoltage > Disable high side FET Thermal Shutdown on over temp. Restore on cool down Good thermal contact to PCB for heat removal Produce 5V with a LDO from higher voltage Current monitor 1000:1 Sense FET or 10 mV Resistor shunt Under voltage Input protection External Protection > Limit Absolute Max Power Supply Voltage Slow Turn on but NO SLOW TURN OFF- Inductive Kick ??? ASIC to have slow Turn off Adjusted Efficiency vs O utputC urrentforM AX8654 #2 Vin = 12V Vout= 1.2V 0 10 20 30 40 50 60 70 80 90 100 0 0.5 1 1.5 2 2.5 3 O utputC urrent(A ) Efficiency (% ) W ith B ias C urrenttaken into account O riginalCurve O utputR esistance versus O utputC urrentfor M AX8654 #2 0 20 40 60 80 100 120 0 0.5 1 1.5 2 2.5 3 O utputC urrent(A ) Resistance (m Ω) E ffective O utputResistance Effect of output Conductance Non Linear output Conductance Stage 1 Stag 2 4088 Cables 10 Chip Hybrid – SCT Module for LHC Counting House 3.5 V 20 Chip Hybrid – Si Tr Module for Hi Luminosity Cable Resistance = 4.5 Ohms 1.5 amps 2.4 amps 20 Chip Hybrid – Si Tr Module for Hi Luminosity 1.3 V 1.3 V 2.4 amps 10.25 V 12.1V 14.08 V 13 V Voltage Drop = 6.75 V Voltage Drop = 10.8V 0.24 amps Voltage Drop = 1.08 V Length of Power Cables = 140 Meters 2 Cascaded Stages Each Stage Efficiency = 0.8 Overall Efficiency = 0.64 Vin Vout Noise from Buck cab be easily shielded Efficiency (%) 0 0.5 2.5 1.5 1.0 2.0 3.0 0 10 20 30 40 50 60 70 80 90 100 Output Current (amps) A proximity effect is seen in the spiral coils Medium coils together 62 mil, 2 oz Cu towards coils 15 mil, 2 oz Cu towards coils 15 mil, 2 oz Cu away from coils 62 mil, 2 oz Cu away from coils Medium coils apart Vout = 2.5 / 1.3 V 6 amps Enable GND Power Good Small Plug-in Card GND Vin= 12 V Size = 2 cms x 3cms Power to Hybrids Coils under Development By William B. Kuhn @ Kansas State University Evaluation Boards
CMS ECAL Powering
Jan 03, 2016
Length of Power Cables = 140 Meters. Length of Power Cables = 140 Meters. 3.5 V. 3.5 V. Cable Resistance = 4.5 Ohms. Cable Resistance = 4.5 Ohms. 10 Chip Hybrid – SCT Module for LHC. 10 Chip Hybrid – SCT Module for LHC. 10.25 V. 10.25 V. 4088 Cables. 4088 Cables. Voltage Drop = 6.75 V. - PowerPoint PPT Presentation
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CMS ECAL PoweringCMS ECAL Powering
What Have we Learned from the Commercial Buck Converters?What Have we Learned from the Commercial Buck Converters?S. Dhawan, O. Baker, H. Chen R. Khanna, J. Kierstead, D. Lynn, A. Mincer , A. Musso
S. Rescia, H. Smith, P. Tipton, M. Weber
AbstractAbstractCommercial power converters that have voltage ratios greater than ten and are capable of running near the LHC collision region would increase the efficiency of the power distribution system of the ATLAS Silicon Tracker high luminosity upgrade. The devices must operate in a high magnetic field (2 T) and be radiation hard to ~50-100 Mrad and ~1015 Neq/cm2. These converters are to be mounted on the same multi-chip modules as the ASIC readout chips or in close vicinity without introducing any additional readout noise due to the high switching frequencies. Such devices will permit higher voltage power delivery to the tracker and thus increase overall power efficiency by limiting the ohmic losses in the stretch of cable (about 100 meters) between the tracker and the power sources.
Power Distribution Schemes and Efficiencies
10:1 Voltage Ratio Converter10:1 Voltage Ratio Converter
Need for New methods of Power DistributionNeed for New methods of Power Distribution Presently LHC inner detector electronics use DC power supplies located in the counting house that feed low voltage power over a long distance (30 m for CMS and 140 m for ATLAS detector). Here we focus on the powering of the silicon tracker for the high luminosity LHC that shall result in x10 higher luminosity and use x10 more detecting elements. The “Power Delivery with Existing SCT Cables” plot illustrates the problem. At present 10.25 V power from the counting house is delivered by 4088 power cables each with a resistance of 4.5 Ω. The 10 chip ASIC readout chip hybrid Kapton PCB needs 1.5 amps @ 3.5 Volts. The bar graph shows the power delivery efficiency of ~33%. In an upgraded ASIC design with finer lithography and x2 more chips, the voltage drops to 1.3 V and with the same cables the power delivery efficiency drops to 10%. By inserting a DC-DC with x10 voltage converter on the 20 chip hybrid Kapton PCB, the efficiency climbs to over 80%.
2008 Radiation Damage Tests2008 Radiation Damage Tests
There is a clear need for a new system of power delivery to the upgraded Atlas Silicon Tracker for the SLHC. Conventional powering will result in an efficiency of power delivery to the detector of about 10% with existing cables whose size are limited in cross section due to space and mass constraints. A system featuring DC-DC converters with voltage ratios of ten will result in an estimated efficiency on the order of 70-80% with existing cables.
One approach to DC-DC conversion utilizes the buck regulator architecture. As DC-DC buck converters are commonly used in the commercial market, we have been surveying and testing currently available devices to understand the present state of the art.
Yale University, Brookhaven National Laboratory, National Semiconductor Corp, Rutherford Appleton Laboratory, New York University & Rutherford Appleton Laboratory
Device Time in
Seconds
Dose before Damage
Seen (krad)
Observations
Damage Mode
TPS 62110 720 40 Increasing input current
ISL 8502 730 40.6 Increasing input current
MAX 8654 850 47.2 Loss of output voltage regulation
ADP 21xx 1000 55.6 Loss of output voltage regulation
ST 1S10 2250 125 Loss of output voltage regulation
IR3822 2500 139 Increasing input current
EN5382 2000 111 Loss of output voltage regulation
EN5360 #3 864000 48 Mrad MINIMAL DAMAGE
EN5360 #2 TESTED IN 2007 100 Mrad MINIMAL DAMAGE
Enpirion:Enpirion:
In our radiation testing Enpirion device EN5360 has outlasted all other irradiated devices from all manufacturers, while the similar EN5365 and EN5382 failed. The EN5360 was made by IHP Microelectronics foundry in Germany while successor devices are fabricated by Dongbu HiTek semiconductor in South Korea. Both are on 0.25 m CMOS process, but some differences in the foundry processes and perhaps in the device circuit design make the EN5360 radiation hard. Recently Los Alamos National Laboratory irradiated an EN5360 and its successor EN5365 with heavy ions and protons for space satellite use. Their conclusion is that while both are suitable for their purposes, the EN5360 showed no effect up to their proton dosage limit while EN5365 failed.
Enpirion EN5360 is a proof of principle that a commercial COTS device can be radiation hard. In our visit to the HP factory in Nov 2008, it was revealed that they have developed 12 Volt FET transistors in the same process. This is essential for a 10:1 Voltage conversion BUCK. Samples of these transistors have been irradiated to levels exceeding those expected at the SLHC. We are attempting to understand differences in the IHP fabrication process that lead to a successful device. Additionally, as next generation devices come on the market we will use the infrastructure we developed to quickly evaluate these devices
Conclusions/ Future WorkConclusions/ Future Work
Air Coils Proximity Effect increases Losses
4088 Cables10 Chip Hybrid – SCT Module for LHC
Counting House
3.5 V
20 Chip Hybrid – Si TrModule for Hi Luminosity
Cable Resistance = 4.5 Ohms
1.5 amps
2.4 amps
20 Chip Hybrid – Si TrModule for Hi Luminosity
1.3 V
1.3 V
2.4 amps
10.25 V
12.1V
14.08 V13 V
Voltage Drop = 6.75 V
Voltage Drop = 10.8V
0.24 ampsVoltage Drop = 1.08 V
Length of Power Cables = 140 Meters
Power Delivery with Existing SCT Cables (total = 4088)Resistance = 4. 5 Ohms
0
10
20
30
40
50
60
70
80
90
100
3.5 V @ 1.5 amps 1.3 V @ 2.4 amps 1.3 V @ 2.4 ampswith x10 Buck
switcher. Efficiency90%
Voltage @ Load
Po
we
r E
ffici
en
cy %
Efficiency
Eff
icie
ncy
(%)
Output Current (amps)
Enpirion 5360 before and after radiation, Vin = 5.5V
Note – Device #2 Survived Previous Radiation Run #3 Aug-4-2008
#2 Aug-4-2008
#3 Aug-29-2008#1 Aug-4-2008
0
10
20
30
40
50
60
70
80
90
100
0 0.5 4.53.52.51.51.0 2.0 3.0 4.0
X 10 DC-DCPower
Converter
1 CMS Trigger Tower
CMS 32.K Trigger Towers = 50 K amps
ENB
LDO
1.2V
CMS 32.K Trigger Towers = 50,000 amps
12V
10:1 Buck Converter
5 V
Low Cost: An ASIC + Inductor + Caps10:1 Voltage Ratio @ 1 MHz High Side switch on for 100 nsec Low Side switch on for 900 nsec High Speed CMOS Switching Processor Switching Losses – High Side Conduction Losses – Low Side In Future speed increase to 20 MHz
Buck Regulator Efficiency after 100 Mrad dosage
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
90.00
0.000 1.000 2.000 3.000 4.000 5.000 6.000
Output Current Amps
Po
we
r E
ffic
ien
cy
AfterExposure
BeforeExposure
February 2007
Tests Done in 2007 Radiation Test – Enpirion 6 amp Device 0.25 µm CMOS – 100 Mega rads Evaluation Boards: Enpirion, Linear Technology, Micrel, MPS, TI etc
Air Coil Tests on Chips with External Inductors
Pick up Noise: RHIC Polarimeter Silicon with Analog Readout RF Leakage
Noise and Pickup Tests - ATLAS Silicon Tracker Module at RAL
Magnetic Field Vout increased 1in 900 @ 7T Load Efficiency Tests
Noise Same PCB Tests: DC-DC Converter on the Hybrid @ BNL & Yale
Antenna Effect Tests
After 100 M rads
Before
Si Sensor 8x10 cms
Si Sensor 8x10 cms
Buck
7 Tesla SuperconductingMagnet: Persistent Mode
Tests Done in 2008 Radiation Test – A dozen devices-
Why are Enpirion chips (IHP Foundry) Rad Hard ?
Combination of Foundry & Circuit Design
Discuss with IHP, Chip Designers, etc
Air Coil Developments
Load Efficiency Tests for 10:1 Voltage Conversion ratio
Features inside a Buck Chip Power Down: Low power mode. Shut output switches Output High side current limit pulse by pulse (turn off high side FET. After 16 times go to soft Start) Output Low side current limit pulse by pulse (turn off low side FET) Power OK if Vout with in 10% of set voltage Vout overvoltage > Disable high side FET Thermal Shutdown on over temp. Restore on cool down Good thermal contact to PCB for heat removal Produce 5V with a LDO from higher voltage Current monitor 1000:1 Sense FET or 10 mV Resistor shunt Under voltage Input protection External Protection > Limit Absolute Max Power Supply Voltage
Slow Turn on but NO SLOW TURN OFF- Inductive Kick ??? ASIC to have slow Turn off
Adjusted Efficiency vs Output Current for MAX8654 #2 Vin = 12V Vout= 1.2V
0
10
20
30
40
50
60
70
80
90
100
0 0.5 1 1.5 2 2.5 3
Output Current (A)
Eff
icie
ncy
(%
)
With Bias Current taken into account Original Curve
Output Resistance versus Output Current for MAX8654 #2
0
20
40
60
80
100
120
0 0.5 1 1.5 2 2.5 3
Output Current (A)
Res
ista
nce
(m
Ω)
Effective Output Resistance
Effect of output Conductance
Non Linear output Conductance
Stage 1 Stag 2
4088 Cables10 Chip Hybrid – SCT Module for LHC
Counting House
3.5 V
20 Chip Hybrid – Si TrModule for Hi Luminosity
Cable Resistance = 4.5 Ohms
1.5 amps
2.4 amps
20 Chip Hybrid – Si TrModule for Hi Luminosity
1.3 V
1.3 V
2.4 amps
10.25 V
12.1V
14.08 V13 V
Voltage Drop = 6.75 V
Voltage Drop = 10.8V
0.24 ampsVoltage Drop = 1.08 V
Length of Power Cables = 140 Meters
2 Cascaded Stages
Each Stage Efficiency = 0.8
Overall Efficiency = 0.64
Vin Vout
Noise from Buck cabbe easily shielded
Eff
icie
ncy
(%)
0 0.5 2.51.51.0 2.0 3.00
10
20
3040
50
60
7080
90
100
Output Current (amps)
A proximity effect is seen in the spiral coils
Medium coils together
62 mil, 2 oz Cu towards coils
15 mil, 2 oz Cu towards coils
15 mil, 2 oz Cu away from coils
62 mil, 2 oz Cu away from coils
Medium coils apart
Vout = 2.5 / 1.3 V 6 amps
EnableGND
Power Good
Small Plug-in Card
GND
Vin= 12 V
Size = 2 cms x 3cms
Power to Hybrids
Coils under Development By William B. Kuhn
@ Kansas State University
Evaluation Boards
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