IEEE Consumer Electronics Magazine - January/February 2022 - 93

Table 6. Transistors Count in EE-SPFAL-Based TSAA,
TCAA, and CMOS-Based Adders.
CMOS AMA8
PMOS NMOS Total
12
12
CMOSapx19 88
CMOSapx29 77
CMOSapx39 65
CMOSapx49 56
EE-SPFAL TSAA
EE-SPFAL TCAA
2
2
14
12
24
16
14
11
11
16
14
Table 7. MED Value of EE-SPFAL-Based TSAA, TCAA, and
CMOS-Based Approximate Adders.
CMOSapx19
CMOSapx29
CMOSapx39
CMOSapx49
EE-SPFAL TSAA
EE-SPFAL TCAA
1-b adder
0.250
0.250
0.500
0.375
0.500
0.250
4-b adder
2.719
3.617
4.426
5.000
5.515
3.617
CONCLUSION
We illustrated that low-power and secure soladders9,
EE-SPFAL-based TSAA, and EE-SPFALbased
TCAA is shown in Table 6. From Table 6,
both proposed designs have less transistor than
CMOS-based AMA. EE-SPFAL-based TSAA has
33% fewer transistors, and EE-SPFAL-based
TCAA has 41.7% fewer transistors compared to
CMOS AMA.
Mean Error Distance
In this section, we are presenting the accuracy
of both proposed adders. The mean error
distance (MED) is the metric to determine the
accuracy of the approximate circuits. The accuracy
is inversely proportional to MED value. The
smaller the MED value, the better is the accuracy
of the approximate circuit. The MED values are
computed with (6), where error distance ( ED) is
the difference between the exact output and the
approximate output for a given input, P is the
probability of the ED, and n is the number of bit
of the adder
MED ¼
ED ¼jOutacu Outapxj
EDsn PðEDsnÞ:
X
n
(6)
utions for edge computing can be developed by
the hybridization of approximate computing and
adiabatic logic. Based on dual-rail adiabatic
logic, two novel AAAs are proposed. The findings
show a substantial decrease in power and
energy consumption in the approximate adders
based on the adiabatic logic compared to the
traditional CMOS design. Furthermore, they are
protected from DPA attacks. It is concluded that
the proposed adiabatic TCAA offers more energy
and power savings, has less transistors, and has
better accuracy. The adiabatic TSAA, however,
offers greater resistance to DPA attacks.
ACKNOWLEDGMENTS
This work was supported by the National Science
Foundation CAREER under Award 1845448.
&REFERENCES
1. S. P. Mohanty, " Security and privacy by design is key
in the Internet of Everything (IoE) era, " IEEEConsum.
Electron. Mag., vol. 9, no. 2, pp. 4/5, Mar. 2020.
2. M. Satyanarayanan, " The emergence of edge
computing, " Computer, vol. 50, no. 1, pp. 30-39, 2017.
Table 7 presents the MED value of approximate
adders. The MED value of EE-SPFAL-based
4-b TCAA is 3.617, which is the 2nd lowest value.
However, the MED value of EE-SPFAL-based 4-b
TSAA is 5.515, which is the highest value among
all approximate adders. We can conclude that
the EE-SPFAL-based TCAA has better accuracy
than EE-SPFAL-based TSAA.
January/February 2022
3. P. Yellu, N. Boskov, M. A. Kinsy, and Q. Yu, " Security
threats in approximate computing systems, " in Proc.
Great Lakes Symp. VLSI, 2019, pp. 387-392.
4. F. Regazzoni, C. Alippi, and I. Polian, " Security: The
dark side of approximate computing?, " in Proc. IEEE/
ACMInt. Conf. Comput.-AidedDes., 2018, pp. 1-6.
5. M. Gao, Q. Wang, M. T. Arafin, Y. Lyu, and G. Qu,
" Approximate computing for low power and security
in the Internet of Things, " Computer, vol. 50, no. 6,
pp. 27-34, 2017.
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