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A complete DC/DC converter ASIC for LHC upgrades S. Michelis, F. Faccio, G. Blanchot, I. Troyano CERN PH-ESE S.Saggini University of Udine, Italy Twepp 2012, Oxford 17-21 September 2012 1
A complete DC/DC converter ASIC
for LHC upgradesS. Michelis, F. Faccio, G. Blanchot, I. Troyano
CERN PH-ESE
S.SagginiUniversity of Udine, Italy
Twepp 2012, Oxford 17-21 September 2012
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S. Michelis, Twepp 2012, Oxford
Power distribution with DC-DC convertersBuck Converter
Specifications:Vin<=10VVout=1.2-3.3VIout<=3Afrequency=1-3 MHz
Constrains:magnetic (2T-4T) fieldsradiation (TID>100Mrd, fluence > 2 1015 p/cm² ions with
LET<40MeV·cm²/mg)
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DC/DC ASIC
S. Michelis, Twepp 2012, Oxford
aMis 53
S. Michelis, Twepp 2012, Oxford2.88mm
2.7
mm
AMIS5 is designed in a High Voltage 0.35um technology for automotive application.
This technology has been successfully tested for TID, protons and heavy ions.
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S. Michelis, Twepp 2012, Oxford
High Side transistors
Low Side transistors
Analog Linear regulators
Digital Lin. Regulator capacitors
Control Circuit
Buffer / Drivers
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S. Michelis, Twepp 2012, Oxford
Two AMIS5 versions have been submitted (same dimension, same pinout)
BOLL
(Buffer Overcurrent=Large Low)faster turn on&off of power transistorsOver-Current detection on Low Side Transistor
BOSH (Buffer Overcurrent=Small High)slower turn on&off of power transistorsOver-Current detection on High Side Transistor
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Buffers
S. Michelis, Twepp 2012, Oxford
the ASIC is OFF by default•the Enable pin need to be
externally controlled. •AMIS5 turn on if Venable>0.7V
(compatible with 1.2V logic up to 3.3V)
AMIS5 Enable
0.7V
Internal Enable
External Pull-upVoltage (<3.3V)
RExt
Power Good
ENABLE POWER GOOD
• Power Good: is an open drain pin.
• Power Good goes high if:✓ AMIS5 is enabled,
Vin>5V and it is working properly
• Power Good goes low (zero) when AMIS5 is supplied (Vin>5V) and if it is in one of these conditions:
‣ Start-up‣ Over-Current limitation‣ Over-Temperature limitation‣ AMIS5 disabled8
S. Michelis, Twepp 2012, Oxford
Only 2/5th of the power transistors are operative. Higher efficiency for small load (<1A)
ENABLE Half Swith
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S. Michelis, Twepp 2012, Oxford
Input Under – Voltage Protection
time (s)
5V
4V
converteroff
converteroff
converteron
Vin
Vin
Threshold
Vin Enabler for
the converter
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S. Michelis, Twepp 2012, Oxford
Over-Temperature Protection
time (s)
converteron
Temperature
100°C
converteron
60°C
converteroff
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S. Michelis, Twepp 2012, Oxford
Over-current protection
S. Michelis, Twepp 2012, Oxford
AMIS5 Efficiency
with Vin=10V, L=460nH, Vout=2.5V, f=1.7MHz13
S. Michelis, Twepp 2012, Oxford
Efficiency for different Vout
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S. Michelis, Twepp 2012, Oxford
Iout=0A
Iout=0.5AIout=1A
Iout=1.5A
Iout=2AIout=2.5A
Iout=3A
@ f=1.7MHz, L=460nH
Line and Load regulation
Line regulation: 4mV variation with Vin=6V-12V
Load regulation: 7mV variation with Iout=0A-3A15
S. Michelis, Twepp 2012, Oxford
Load Transient
Load transient setup thanks to Cristian Fuentes
S. Michelis, Twepp 2012, Oxford
TID tests
with Vin=10V, L=460nH, Vout=2.5V, f=1.7MHz17
pre-rad
S. Michelis, Twepp 2012, Oxford
TID Tests at different temperature
with Vin=10V, L=460nH, Vout=2.5V, f=1.7MHz
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pre-rad
S. Michelis, Twepp 2012, Oxford
pre-rad
Line and Load regulations vs TID
with Vin=10V, L=460nH, Vout=2.5V, f=1.7MHz
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S. Michelis, Twepp 2012, Oxford
Future plans
2.88mm
3.3
mm
AMIS5_BB
• Test foreseen for AMIS5
Single Event and Displacement damage tests (fall 2012)
BOSH version tests
Tests on AMIS5 packaged in QFN32
• AMIS5_BB Bump Bonded version
tests and characterization (expected back in November 2012)
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S. Michelis, Twepp 2012, Oxford
NegativeConverter
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S. Michelis, Twepp 2012, Oxford
Positive ConverterNegative Converter
Vin
DC/DC
VoutPhase
-Vout For the time being the DC/DC converter is a commercial chip (LTC3605, the same for SM01C).It will be replaced with AMIS5
28.5 mm
13.5 mm
Differential Mode noiseNegative Converter
Differential Mode noisePositive Converter
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Board designed by Isaac Troyano
S. Michelis, Twepp 2012, Oxford
Conclusions• A new DC/DC converter ASIC called AMIS5 has been presented.
It is a fully integrated synchronous buck converter which contains internal linear regulators, bandgaps and a control circuitry to handle signals form the protection circuitryEfficiency is high (above 80%, peak 83%-85%)Radiation effects are limited (2-4% loss of efficiency over 325Mrad and Iout=2-3A)line regulation is good (4 mV for Vin variation from 6 to 12V)load regulation is good (7 mV for Iout variation from 0 to 3A)
• A negative converter has been presentedIt allows to convert a positive input voltage to a negative voltage (e.x. Vin=7V and Vout=-2.5V). It uses a chip that has been already used for a positive convert. Only the PCB layout is changed. AMIS5 will replace the commercial component for radiation tolerance
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