Accelerating neural networks in hardware using interconnected crossbars

A method of configuring a computing unit for accelerating a neural network, the method comprising:

• configuring a plurality of interconnected analog crossbar circuits comprising a first analog crossbar circuit, a last analog crossbar circuit, and a set of intermediary analog crossbar circuits between the first analog crossbar circuit and the last analog crossbar circuit, wherein:
• each interconnected analog crossbar circuit corresponds to a respective layer of the neural network and includes a plurality of crosspoints, each crosspoint storing a weight of a plurality of weights associated with the respective layer of the neural network,
• wherein each analog crossbar circuit in the set of intermediary analog circuits receives an analog input from a preceding analog crossbar circuit and provides an analog output to a subsequent analog crossbar circuit;
• configuring a single digital-to-analog conversion (DAC) unit to convert a digital input vector into a first analog signal that is provided as an input to the first analog crossbar circuit;
• and
• configuring a single analog-to-digital conversion (ADC) unit to receive as an input a second analog signal from an output of the last analog crossbar circuit and convert the second analog signal into a digital output vector.

A non-transitory computer storage medium encoded with a computer program, the program comprising instructions that are operable, when executed by a data processing apparatus, to cause the data processing apparatus to perform the operations comprising:

• configuring a plurality of interconnected analog crossbar circuits comprising a first analog crossbar circuit, a last analog crossbar circuit, and a set of intermediary analog crossbar circuits between the first analog crossbar circuit and the last analog crossbar circuit, wherein:
• each interconnected analog crossbar circuit corresponds to a respective layer of a neural network and includes a plurality of crosspoints, each crosspoint storing a weight of a plurality of weights associated with the respective layer of the neural network,
• wherein each analog crossbar circuit in the set of intermediary analog circuits receives an analog input from a preceding analog crossbar circuit and provides an analog output to a subsequent analog crossbar circuit;
• configuring a single digital-to-analog conversion (DAC) unit to convert a digital input vector into a first analog signal that is provided as an input to the first analog crossbar circuit;
• and
• configuring a single analog-to-digital conversion (ADC) unit to receive as an input a second analog signal from an output of the last analog crossbar circuit and convert the second analog signal into a digital output vector.