11 1 University of Michigan 1 Phoenix: An Ultra-Low Power Processor for Cubic Millimeter Sensor...
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Transcript of 11 1 University of Michigan 1 Phoenix: An Ultra-Low Power Processor for Cubic Millimeter Sensor...
11
1
University of Michigan 1
Phoenix: An Ultra-Low Power Processor for Cubic Millimeter Sensor System
Motivations
Sensor application requires small form factor and long lifetime
Both limited by battery - A 1mm2 zinc/silver battery with 100µAh/cm2 can provides 177pW for 1 year lifetime
Either improve battery or power consumption
Minimize standby power (dominating portion of total power) via comprehensive standby strategy
Bravo® pH Monitoring System
VeriChipTM RFID Tag
VeriChip
Previous Platform[1] Zhai, et al.
[2] Hanson, et al.
This work
Co
mp
reh
ens
ive
Sle
ep
Str
ate
gy
Subthreshold Operation~pJ Per Inst.
Eactive
Ps
lee
p3
4pW
~1
00nW
~2
500X
Zhai, et al. [1]
Hanson, et al. [2]
This work
Tech
0.18um
0.13um
0.18um
E/cycle
2.6pJ
3.5pJ
2.8pJ
Pstandby
238nW
154nW
34pW
22
2
University of Michigan 2
CPU52x40DMEM
64x10IMEM
128x10IROM
PowerManagement
I/OClock
Generator
Com
press/D
ecom
press
TimerTemperature
Sensor
System Bus
Power gated
Partially gated Not gated
...
...
915um
915u
mComprehensive standby strategy
Optimum technology selection L=0.18µm, Vdd=0.5V given performance, duty
cycle and memory requirements
Unique power gating approach SVT MOSFET with W=0.66µm L=0.5µm
Tradeoff performance with standby power
Ultra-low leakage sub-VTH SRAM design 7.1fW/bit custom SRAM cell
Adaptive power gating for dynamic standby power management
Power gating for peripherals
Robust ultra-low Vdd ROM design full static NAND ROM design for robustness
Simple ISA with compression support Narrow instruction for small IMEM footprint
Ultra-low power peripheral unit design Slow watchdog timer
Low power temperature sensor
33
3
University of Michigan 3
Active Mode Sleep Mode0
20
40
60
80
100
CPU
IROM
IMEM
DMEM
2.8pJ/cycle, 297nW 29.6pW
Timer
IROM
IMEM
DMEM
CPU[%]
time
297nW
29.6pW
Pow
er C
onsu
mpt
ion
1 9 m s1 0 m i n
2 0 0 0
i n s t
Results
29.6pW for standby mode and 2.8pJ/cycle for active mode
100kHz at Vdd=0.5V
1mm2 in 0.18µm CMOS technology
2000 instructions for every 10min gives Eactive=5.6nJ, Estandby=17.8nJ
Theoretically 15 year lifetime with a 1mm2 thin film lithium battery
Future works – designing more low power sub-modules including communication link, improve existing modules, variation compensation method, and system-level integration
Thank you!