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DynapSEL

Dynap-sel - A mixed-signal multi-core spiking chip for models of cortical computation implemented in advanced ST 28nm FDSOI process.

DynapSEL

DynapSEL is a five-core fully-asynchronous mixed-signal spiking neural network chip with on-chip learning (STDP) fabricated in 28nm FDSOI process with a silicon area of 2.8mm x 2.6mm. The chip comprises 4 TCAM cores with 1k analog leaky I&F neurons and 64k 15-bit TCAM synapses sub-divided in 4 cores, 1 learning core with 64 analog leaky I&F neurons, 8k digital 4-bit plastic synapses, and 8k 4-bit digital configurable synapses. In addition it integrated 5 LUTs with totally 8.5k x18-bit SRAMs. 3-level hierarchical routers, 2 low temperature coefficient Bias Generators supplying totally 190 branches of biases, on-chip monitors for real-time monitoring on-chip internal currents. 4 26-bit Bi-directional buffers are added in four directions for chip extensions.

die photo of DynapSEL

 

 

 

 

 

 

 

 

 

 

 

 












Hierarchical routing scheme

dynapSEL routing

Chip information

Chip NameDynapSEL
Process ST 28nm FDSOI
Supply Voltage 0.73V - 1V
IO Number 176
Chip area 2.8mm x 2.6mm
Core Numbers 4 non-plastic cores +  1 plastic core
Neuron Type Analog AExp I&F  
Neuron Area 20um^2
Non-plastic Synapse Type TCAM based 4-bit
Non-plastic Synapse Area 7.69um^2
Plastic Synapse Type Linear 4-bit digital
Plastic Synapse Area 72.5um^2
Throughput of Router 1G Events/second
Scalability 16 x16 chips non-plastic core)  / 4 x4 chips (plastic cores)

Comparing with TrueNorth

True NorthThis work 
Technology 28nm CMOS 28 nm FDSOI
Supply Voltage 0.7V 0.73V
Neuron Type Digital Analog
Neurons per core 256 256
On-line Learning No On-line STDP
Core Area 0.094 mm^2 0.36 mm^2
Computation Time multiplexing Parallel processing
Fan In/Out 256/256 2k/8k
Synaptic Operation per Second per Watt 46 GSOPS/W 320 GSOPS/W
Energy per synaptic event 10 pJ 2.8pJ

On line STDP

 

 STDP1


STDP2

On line tiny current monitors

up to 23 current monitors (current to frequency converter) are placed on chip for real-time monitoring tiny currents (pA-100nA). 

C2F