An Asynchronous Spike Event Coding Scheme for Programmable Analog Arrays

This paper presents a spike time event coding scheme for transmission of analog signals between configurable analog blocks (CABs) in a programmable analog array. The analog signals from CABs are encoded as spike time instants dependent upon input signal activity and are transmitted asynchronously by employing the address event representation protocol (AER), a widely used communication protocol in neuromorphic systems. Power dissipation is dependent upon input signal activity and no spike events are generated when the input signal is constant. Computation is intrinsic to the spike event coding scheme and is performed without additional hardware. The ability of the communication scheme to perform computation will enhance the computation power of the programmable analog array. The design methodology and analog circuit design of the scheme are presented. Test results from prototype chips implemented using a 3.3-V, 0.35-μm CMOS technology are presented.