9/08/05 ELEC5970-001/6970-001 Lecture 5 1 ELEC 5970-001/6970-001(Fall 2005) Special Topics in Electrical Engineering Low-Power Design of Electronic Circuits Dual-Threshold Low-Power Devices Vishwani D. Agrawal James J. Danaher Professor Department of Electrical and Computer Engineering Auburn University http://www.eng.auburn.edu/~vagrawal [email protected]
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9/08/05ELEC5970-001/6970-001 Lecture 51 ELEC 5970-001/6970-001(Fall 2005) Special Topics in Electrical Engineering Low-Power Design of Electronic Circuits.
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9/08/05 ELEC5970-001/6970-001 Lecture 5 1
ELEC 5970-001/6970-001(Fall 2005)Special Topics in Electrical EngineeringLow-Power Design of Electronic Circuits
Dual-Threshold Low-Power Devices
Vishwani D. AgrawalJames J. Danaher Professor
Department of Electrical and Computer EngineeringAuburn University
• vth (thermal voltage, kT/q) and Vt both depend on the temperature; leakage current also strongly depends on temperature.
• Spice simulation shows that for a 2-input NAND gate
- with low Vt, Isub @ 90ºC = 10 × Isub @ 27ºC
- with high Vt, Isub @ 90ºC = 20 × Isub @ 27ºC • To manifest the projected contribution of leakage to the
total power, we compare dynamic and leakage power @ 90ºC.
t
ds
th
gsth
eff
effoxsub V
V
nv
VVev
L
WCuI
t
exp1exp8.120
9/08/05 ELEC5970-001/6970-001 Lecture 5 22
Results-Dynamic & Leakage Comparison (cont.)
• Without considering glitches, the dynamic power is estimated by an event driven simulator, and is given by
• We apply 1000 random test vectors at PIs with a vector period of 120% Tc, and calculate the total number of weighted (by node capacitance) transitions in the circuit.
c
ii
iddinvdyn
dyn T
FOTVC
T
EP
2.11000
5.0 2
9/08/05 ELEC5970-001/6970-001 Lecture 5 23
Dynamic & Leakage Power (cont.)
CircuitPdyn
(μW)
Pleak1
(μW)
Pleak1/
Pdyn %Pleak2
(μW)
Pleak2/
Pdyn %
C432 71.17 26.20 36.8 10.22 14.3
C499 149.81 42.93 28.7 34.64 23.1
C880 135.19 44.06 32.6 5.24 3.8
C1355 162.39 43.88 27.0 32.90 20.3
C1908 185.60 60.23 33.4 20.23 10.9
C2670 92.64 59.25 64.0 6.59 7.1
C3540 218.41 156.22 71.5 9.72 4.4
C5315 299.61 193.32 64.6 25.05 8.4
C6288 215.12 231.42 108.0 60.75 28.2
C7552 229.13 220.43 96.2 8.72 3.8
9/08/05 ELEC5970-001/6970-001 Lecture 5 24
Dynamic & Leakage Power (cont.)
9/08/05 ELEC5970-001/6970-001 Lecture 5 25
Leakage and Dynamic Glitch Power Minimization Using Integer Linear