A 60MHz 50W Fine-Grain
Package-Integrated VR
Powering a CPU from 3.3V
Gerhard Schrom, Fabrice Paillet, Jaehong Hahn
Circuit Research Lab, Intel Labs, Intel Corporation
Motivation
y Reduce platform power delivery complexity & area
y Reduce load line & save power
y Enable fine-grain power management
Example: Dell* XPS* M1210
Power delivery
top
bottom
*Other names and brands may be claimed as the property of others
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Intel Labs
Package-Integrated VR
Proof of Concept
y Advantage of on-package 2nd VR stage
– Single 3.3V input, lower current going into the package
– 2-stage conversion is more efficient
– Near-load VR allows fast response, reduced load line
y VR test chip on the CPU package (MCP)
– VR chip/w cascode bridges manufactured in 130nm CMOS
– 60MHz switching frequency allows miniaturization
– Mounted on modified CPU package/w package trace inductors
or powdered-iron core inductors
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Intel Labs
Package-Integrated VR with
Intel® Core™2 Duo Processor
package trace inductors
U
CP
CP
U
IV
IV
R
R
discrete inductors
y Vin=3.3V, Vout=0...1.6V (VID), 10MHz...100MHz,
TDC=50A / 75A peak, size=37.6mm2, 130nm CMOS
y Inductors: 0508-size discrete powdered iron core or
package-trace air core
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FUNCTIONAL BLOCK DIAGRAM
VIN
Integrated VR
Architecture
y Type-3 compensator
XBR[0]
Ramp
Gen.
XBR[1]
x0.8
OV
1.65V
LVR
XBR[2]
8b DAC
XBR[3]
VRef
VDA[7:0] +/- off.
PWM
compensator
VSNS1
GSNS1
x0.8
XBR[4]
2x Digital
Ramp
Gen.
2x Analog
XDPSLP
XPSI_B
XPWGD
Power Mode
LUT
y Progr. ramp rate
y Progr. load line
XVID[3]
XVID[4]
compensator
VSNS2
GSNS2
x0.8
PWGD2
XBR[8]
Ramp
Gen.
EN
XBR[10]
8b DAC
XBR[11]
VRef
VDA[7:0] +/- off.
VID
Decoder
XBR[9]
x0.8
OV
PWM
compensator
UV
XBR[12]
VDA[7:0]
[*] G.Schrom et al. APEC 2007
Intel Labs
Ramp
Gen.
XBR[13]
x0.8
OV
Spread Spectrum
Generator
VSNS3
GSNS3
x0.8
PWGD3
XVID[0]
XCLK
PWM
Delay
XVID[2]
XVID[1]
XBR[7]
VRef
UV
XVRON
XVID[6]
XBR[6]
8b DAC
VDA[7:0] +/- off.
1.65V Bandap
Reference
XBR[5]
x0.8
OV
Test Port
GND
5
VSNS0
GSNS0
x0.8
PWGD1
XVID[5]
y Spread spectrum
EMI control
PWGD0
UV
y Single-output 16-phase
mode/w load balancing
y Cascode bridges [*]
compensator
UV
1.65V
LVR
Control
Registers
y Four voltage domains,
16 phases (4x4)
y Digital voltage control
VIN/2
LVR
XBR[14]
8b DAC
VDA[7:0] +/- off.
XBR[15]
VRef
PWM
Efficiency Measurements
Pkg. air core inductors
90%
90%
85%
Efficiency
Efficiency
85%
0508 pwdr Fe core inductors
80%
100% activation
load adaptive
75%
70%
80%
100% activation
load adaptive
75%
70%
0
10 20 30 40 50 60 70 80
Load Current [A]
0
10 20 30 40 50 60 70 80
Load Current [A]
y Package embedded air core inductors: 84.9%
y Discrete powdered Fe core inductors: 87.9%
y Load adaptive bridge activation improves by >10%
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Performance
Output Voltage Ramp Rate
1V
Performance
0.5V
1µs
SpeedStep® Voltage Transitions
CRL
low latency:
less waste
Time
demand
available
wasted
Time
y Fast output voltage ramp rate: >500mV/μs
y Time-domain fine-grain power management
saves power
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Transient Performance
Integrated VR
10mV
2nd droop
29mV
3rd droop
52mV
MBVR
2µs
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Load-line set to “0”
y 2nd droop:
reduced to 10mV
y 3rd droop:
eliminated
y Reduced load line
saves power
Impedance Measurement
0.012
CPU/w package-integrated VR
Impedance [Ohm]
0.010
CPU on std. package
0.008
0.006
0.004
0.002
0.000
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 1.E+09
Frequency [Hz]
y Load line set to 0.5mΩ, measured 0.42mΩ
[A.Waizman et al. EPEP 2004]
using IFDIM method
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EMI Performance
EMI Level [dBµV/m]
60
Laptop with IVR/w discrete ferrite inductors
Laptop with IVR/w package trace air-core inductors
Unmodified laptop
50
40
FCC Limit
30
20
10
5
30M
50M
70M
100M
200M
Frequency [Hz]
300M
500M
700M 1G
y Laptop modified to use IVR-powered CPU
y CISPR 22B test in 3m EMI chamber, EMC worst-case
y Compliant with spread-spectrum enabled
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Conclusion
y
A high-performance package-integrated VR
was demonstrated powering an
Intel® Core™2 Duo processor from 3.3V
– Peak efficiency of 85-88%
– Fast slew rate of >500mV/μs
– Excellent droop & load line of <0.5mΩ
11
y
A laptop modified to use the IVR-powered
CPU booted successfully
y
The power density at 50W is 11.8kW/in3
Intel Labs