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Power Optimization in VLSI Design :
Tunable Level Shifter
Abu Baker
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Outline
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Objective and Background
CMOS Power Dissipation
CMOS Device Characteristics
CMOS Current Mirror
Design of Level Shifter
Circuit Simulation
Delay and Power Analysis
Leakage Analysis
Comparison Analysis
Summary and Discussion
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Outline
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Objective and Background
CMOS Power Dissipation
CMOS Device Characteristics
CMOS Current Mirror
Design of Level Shifter
Circuit Simulation
Delay and Power Analysis
Leakage Analysis
Comparison Analysis
Summary
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NTRS Technology trends:
200-300M chips by 2010 (0.07 micron CMOS)
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Energy/Power Gap
Power ( K Watts)
100
P6
Pentium ® proc
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8086 286
1
8008
4004
486
Dynamic Growth
386
8085
8080
0.1
1971
1974
1978
1985
Year
1992
2000
Lead Microprocessors power continues to increase
Exponential growth in the # of devices per chip +
Operating frequencies = Dynamic Growth
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Design Objectives
Challenges
VLSI Technology
Power Optimization
(i.e. Management)
Low power
Portable Devices
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Outline
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Objective and Background
CMOS Power Dissipation
CMOS Device Characteristics
CMOS Current Mirror
Design of Level Shifter
Circuit Simulation
Delay and Power Analysis
Leakage Analysis
Comparison Analysis
Summary and Discussion
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CMOS Power Consumption
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Dual Supply Voltage
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Outline
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Objective and Background
CMOS Power Dissipation
CMOS Device Characteristics
CMOS Current Mirror
Design of Level Shifter
Circuit Simulation
Delay and Power Analysis
Leakage Analysis
Comparison Analysis
Summary and Discussion
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CMOS Device Characteristics
Small Signal Model
Bode Plot
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Bandwidth Properties
Small Signal Model
Bode Plot
Unity Gain Frequency
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Outline
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Objective and Background of the Presentation
CMOS Power Dissipation
CMOS Device Characteristics
CMOS Current Mirror
Design of Level Shifter
Circuit Simulation
Delay and Power Analysis
Leakage Analysis
Comparison Analysis
Summary and Discussion
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CMOS Current Mirror
CMOS Current Mirror Circuit
I-V Characteristic of the Active Load Q 2
Graphical Construction to Determine the Transfer Characteristic
Transfer Characteristic
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Outline
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Objective and Background
CMOS Power Dissipation
CMOS Device Characteristics
CMOS Current Mirror
Design of Level Shifter
Circuit Simulation
Delay and Power Analysis
Leakage Analysis
Comparison Analysis
Summary and Discussion
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Circuit Schematic for the Level Shifter
Vref
Out
Vin
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The schematic for the non-stacked output
of the buffer for better rise and fall time
Vref
Out
Vin
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Biasing Circuit
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Outline
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





Objective and Background
CMOS Power Dissipation
CMOS Device Characteristics
CMOS Current Mirror
Design of Level Shifter
Circuit Simulation
Delay and Power Analysis
Leakage Analysis
Comparison Analysis
Summary and Discussion
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Simulation
Simulation for at 250 MHz from 0.65v to 1.2v
Simulation for at 1 GHz from 0.65v to 1.2v
spectre
The simulation was done with the cadence
for the 130nm process for the level shifting from 0.65v and 0.85v to the 1.2v.
The duty cycle was set at 37.5 in order to simulate the random data type that the buffer may be used in real application.
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Outline










Objective and Background
CMOS Power Dissipation
CMOS Device Characteristics
CMOS Current Mirror
Design of Level Shifter
Circuit Simulation
Delay and Power Analysis
Leakage Analysis
Comparison Analysis
Summary and Discussion
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Delay and Power Analysis
Non-stacked transistor data at 250 MHz
Power (W)
53.23
Fall time
(ps)
38.31
56.88
66.83
8.33u
Vin
Rise time (ps)
0.85
0.65
14.09u
Non-stacked transistor data at 1 GHz
0.85
Rise
(ps)
88.4
0.65
56.88
Vin
time
Fall time
(ps)
73.46
66.83
Power (W)
8.989u
9.75u
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Delay and Power Analysis
Stacked transistor data at 250 MHz
Vin
0.85
0.65
Rise time
(ps)
116.6
83.17
Fall time
(ps)
85.9
79.9
Power (W)
6.847u
7.96u
Stacked transistor data at 1 GHz
Vin
Rise time (ps)
0.85
116.6
Fall
(ps)
87.75
0.65
82.77
81.6
time
Power (W)
7.98u
9.3u
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Outline
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Objective and Background of the Presentation
CMOS Power Dissipation
CMOS Device Characteristics
CMOS Current Mirror
Design of Level Shifter through Mirror Circuit
Circuit Simulation
Delay and Power Analysis
Leakage Analysis
Comparison Analysis
Summary and Discussion
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Leakage Analysis
Buffer off (Using PMOS switch)
Vinput
Clk swing 0.85v
Constant 0.85v
Constant 0 v
Pwr Dissipation (W)
1.09u
1.05u
1.049u
Buffer off (Using NMOS switch)
Vinput
Clk swing 0.85v
Constant 0.85v
Constant 0 v
Pwr Dissipation (W)
470n
459n
315n
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Outline
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








Objective and Background of the Presentation
CMOS Power Dissipation
CMOS Device Characteristics
CMOS Current Mirror
Design of Level Shifter through Mirror Circuit
Circuit Simulation
Delay and Power Analysis
Leakage Analysis
Comparison Analysis
Summary and Discussion
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Comparison Analysis
Different
Type of
LC
# of Tr.
Delay
(ps)
Power (uW)
PDP (fJ)
CSSA
30
510
21.7
11.1
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1004
11.3
11.3
32
380
11.8
4.5
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12-14
312
137-245
9.45
14.09-6.847
2.93
1.93-1.7
(Clock-level Shifted SenseAmplifying)
SLLS
(Slave-Latch Level-Shifting)
SPFF
(Self-Precharging FF)
DE_LCFF
CMLC
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M. Hamada, et al., “A top-down low power design technique using clustered voltage scaling with
variable supply-voltage scheme,” Custom Integrated Circuits Conf., pp. 495–498, 1998.
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H. Mahmoodi-Meimand and K. Roy, "Self-precharging flip-flop (SPFF): A new level converting flipflop," in Proc. European Solid-State Circuits Conference 2002, pp.407--410, Sep. 2002.
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Peiyi Zhao, Golconda Pradeep Kumar, Archana C. and Magdy Bayoumi, “A Double-Edge ImplicitPulsed Level Convert Flip-Flop”, Proceedings of the IEEE Computer Society Annual Symposium on
VLSI Emerging Trends in VLSI Systems Design (ISVLSI’04).
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Comparison Analysis
Different
Type of
LC
# of Tr.
Delay
(ps)
Power (uW)
PDP (fJ)
MSCC
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287
9.13
2.62
33
184
15.56
2.863
23
259
9.03
2.341
23
204
8.84
1.81
31
181
9.72
1.755
27
312
9.45
2.93
12-14
137-245
14.09-6.847
1.93-1.7
(Master-Slave, CrossCoupled)
PSA
(Pulsed,Sense Amplifierbased)
MSHL
(Master-Slave, Half-Latch)
PHL
(Pulsed, Half-Latch)
PPR
(Pulsed, Precharged LC)
DE_LCFF
CMLC
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Fujio Ishihara, Farhana Sheikh, Borivoje Nikolic, “Level Conversion for Dual –Supply Systems,”
IEEE Transactions on VLSI Systems, Vol. 12, No. 2, February 2004.
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Outline










Objective and Background of the Presentation
CMOS Power Dissipation
CMOS Device Characteristics
CMOS Current Mirror
Design of Level Shifter through Mirror Circuit
Circuit Simulation
Delay and Power Analysis
Leakage Analysis
Comparison Analysis
Summary and Discussion
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Summary and Discussions
Gate
level power optimization with dual-supply voltages.
Dual-voltage
approach can achieve significant power saving without
degrading timing performance of the circuit.
A tunable
Thus
level shifter has been presented with some power analysis.
this analog buffer could be integrated as part of the analog I/O
ring as oppose to be part of the digital on chip thus saving on
chip space and die size.
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Thank You
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Questions
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Current –Voltage Relationship
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