IEEE Circuits and Systems Magazine - Q2 2022 - 25

V. Outlook
The function and behavior of biological neural
systems inspire the third generation of
neural networks, i.e. Spiking Neural Networks
(SNN). While moving from biological system
to software simulation deprives the energy
efficiency that the brain promises due to the
inherent limitations of the Von Neumann architecture
in general purpose computers, this
challenge has been tackled by the emerging
neuromorphic hardware. In this work, we discussed
the various aspects of neuromorphic
systems, such as the computing models and
their design considerations, as well as hardware
platform and communication systems.
We have also discussed various neuromorphic
systems, which have provided not only
solid foundations for SNN hardware implementation,
but also exciting computing platforms
for a variety of research fields helping
to push forward the frontier of computational
neuroscience and machine intelligence. However,
there are still many areas waiting to be
explored. The research needs in neuromorphic
computing can be categorized into three
areas 1) algorithm and computational model.
2) hardware architecture. 3) emerging device
technologies.
A. Challenges in Model
and Algorithm Design
On the algorithmic level, in-hardware learning
is still a major road block.
The capability of incrementally augmenting
its knowledge base during run time and
adapting itself to the changing environment is
crucial to an intelligent system. In digital neuromorphic
hardware, the memory capacity
not only limits the network size, but also the
size of the neuron/synapse state variables and
the data precision. This restricts the complexity
of learning rules that can be implemented
on the hardware. While advances have been
made in approximating the backpropagation
algorithm in SNNs in recent years [111], the
quality of learning suffers from low precision
of data and weight representations. How to
improve the accuracy of supervised learning
under limited precision of weight and neuron
activities is one of the problems that need to
be solved with high urgency.
Alongside further investigating the traditional
backpropagation algorithms, application
SECOND QUARTER 2022
IEEE CIRCUITS AND SYSTEMS MAGAZINE
25
Table III.
Comparison of the Large-Scale Neuromorphic Systems.
Neuromorphic Chip
Implementation
Technology
TrueNorth
Digital
28 nm
CMOS
# transistors
Neurons per Core
Synapses per Core
Cores per Chip
Chip Area (mm2)
Energy/SOP (pJ)
NoC
Packet Size (bits)
Time
Neuron Update
Bio-Plausibility
Simulation Time
On-Chip Learning
5.4 B
256
256x256
4,096
430
26
2D mesh unicast
32
Discretized
Time Multiplexed
Low
1x to 21x
real-time
No
SpiNNaker
Digital
ARM968
130 nm
CMOS
100 M
~1k
~1M
16
102
10000
2D mesh
multicast
40 + optional 32
Discretized
Real-time
Yes
Loihi
Digital
14 nm
CMOS
2.07 B
max 1024
~16k
128
60
23.6
2D mesh unicast
Discretized
Medium
>Real-time but
variable
Yes
BrainScaleS Neurogrid
Analog
Analog
180 nm
CMOS
15 M
8 to 512
~130k
352
50
100
Hierarchical
30
Discretized
Time Multiplexed Time Multiplexed Real time
Medium
High
Yes
180 nm
CMOS
23 M
65k
100M
16
168
100
Tree multicast
12
Real time
Real time
High
104x to 105x Real-time
No
Real time
Real time
High
70 MHz clock
Yes
Braindrop
Analog
28 nm
CMOS
4096
64k
16
0.38
Tree Multicast
Dynap-SEL
Mixed-signal
180 nm
CMOS
1024
64k
4
43.79
17
Hierarchical 2D
mesh multicast
20
Real time
Real time
High
Real-time
Yes
Real time
Real time
Low
300 MHz
No
Tianjic
Digital
28 nm
CMOS
16
22k
156
14.44
0.95
Hierarchical 2D
mesh multicast

IEEE Circuits and Systems Magazine - Q2 2022

Table of Contents for the Digital Edition of IEEE Circuits and Systems Magazine - Q2 2022

IEEE Circuits and Systems Magazine - Q2 2022 - Cover1
IEEE Circuits and Systems Magazine - Q2 2022 - Cover2
IEEE Circuits and Systems Magazine - Q2 2022 - 1
IEEE Circuits and Systems Magazine - Q2 2022 - 2
IEEE Circuits and Systems Magazine - Q2 2022 - 3
IEEE Circuits and Systems Magazine - Q2 2022 - 4
IEEE Circuits and Systems Magazine - Q2 2022 - 5
IEEE Circuits and Systems Magazine - Q2 2022 - 6
IEEE Circuits and Systems Magazine - Q2 2022 - 7
IEEE Circuits and Systems Magazine - Q2 2022 - 8
IEEE Circuits and Systems Magazine - Q2 2022 - 9
IEEE Circuits and Systems Magazine - Q2 2022 - 10
IEEE Circuits and Systems Magazine - Q2 2022 - 11
IEEE Circuits and Systems Magazine - Q2 2022 - 12
IEEE Circuits and Systems Magazine - Q2 2022 - 13
IEEE Circuits and Systems Magazine - Q2 2022 - 14
IEEE Circuits and Systems Magazine - Q2 2022 - 15
IEEE Circuits and Systems Magazine - Q2 2022 - 16
IEEE Circuits and Systems Magazine - Q2 2022 - 17
IEEE Circuits and Systems Magazine - Q2 2022 - 18
IEEE Circuits and Systems Magazine - Q2 2022 - 19
IEEE Circuits and Systems Magazine - Q2 2022 - 20
IEEE Circuits and Systems Magazine - Q2 2022 - 21
IEEE Circuits and Systems Magazine - Q2 2022 - 22
IEEE Circuits and Systems Magazine - Q2 2022 - 23
IEEE Circuits and Systems Magazine - Q2 2022 - 24
IEEE Circuits and Systems Magazine - Q2 2022 - 25
IEEE Circuits and Systems Magazine - Q2 2022 - 26
IEEE Circuits and Systems Magazine - Q2 2022 - 27
IEEE Circuits and Systems Magazine - Q2 2022 - 28
IEEE Circuits and Systems Magazine - Q2 2022 - 29
IEEE Circuits and Systems Magazine - Q2 2022 - 30
IEEE Circuits and Systems Magazine - Q2 2022 - 31
IEEE Circuits and Systems Magazine - Q2 2022 - 32
IEEE Circuits and Systems Magazine - Q2 2022 - 33
IEEE Circuits and Systems Magazine - Q2 2022 - 34
IEEE Circuits and Systems Magazine - Q2 2022 - 35
IEEE Circuits and Systems Magazine - Q2 2022 - 36
IEEE Circuits and Systems Magazine - Q2 2022 - 37
IEEE Circuits and Systems Magazine - Q2 2022 - 38
IEEE Circuits and Systems Magazine - Q2 2022 - 39
IEEE Circuits and Systems Magazine - Q2 2022 - 40
IEEE Circuits and Systems Magazine - Q2 2022 - 41
IEEE Circuits and Systems Magazine - Q2 2022 - 42
IEEE Circuits and Systems Magazine - Q2 2022 - 43
IEEE Circuits and Systems Magazine - Q2 2022 - 44
IEEE Circuits and Systems Magazine - Q2 2022 - 45
IEEE Circuits and Systems Magazine - Q2 2022 - 46
IEEE Circuits and Systems Magazine - Q2 2022 - 47
IEEE Circuits and Systems Magazine - Q2 2022 - 48
IEEE Circuits and Systems Magazine - Q2 2022 - 49
IEEE Circuits and Systems Magazine - Q2 2022 - 50
IEEE Circuits and Systems Magazine - Q2 2022 - 51
IEEE Circuits and Systems Magazine - Q2 2022 - 52
IEEE Circuits and Systems Magazine - Q2 2022 - 53
IEEE Circuits and Systems Magazine - Q2 2022 - 54
IEEE Circuits and Systems Magazine - Q2 2022 - 55
IEEE Circuits and Systems Magazine - Q2 2022 - 56
IEEE Circuits and Systems Magazine - Q2 2022 - 57
IEEE Circuits and Systems Magazine - Q2 2022 - 58
IEEE Circuits and Systems Magazine - Q2 2022 - 59
IEEE Circuits and Systems Magazine - Q2 2022 - 60
IEEE Circuits and Systems Magazine - Q2 2022 - 61
IEEE Circuits and Systems Magazine - Q2 2022 - 62
IEEE Circuits and Systems Magazine - Q2 2022 - 63
IEEE Circuits and Systems Magazine - Q2 2022 - 64
IEEE Circuits and Systems Magazine - Q2 2022 - 65
IEEE Circuits and Systems Magazine - Q2 2022 - 66
IEEE Circuits and Systems Magazine - Q2 2022 - 67
IEEE Circuits and Systems Magazine - Q2 2022 - 68
IEEE Circuits and Systems Magazine - Q2 2022 - Cover3
IEEE Circuits and Systems Magazine - Q2 2022 - Cover4
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2023Q3
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2023Q2
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2023Q1
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2022Q4
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2022Q3
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2022Q2
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2022Q1
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2021Q4
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2021q3
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2021q2
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2021q1
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2020q4
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2020q3
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2020q2
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2020q1
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2019q4
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2019q3
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2019q2
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2019q1
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2018q4
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2018q3
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2018q2
https://www.nxtbook.com/nxtbooks/ieee/circuitsandsystems_2018q1
https://www.nxtbookmedia.com