A second generation time-to-first-spike pixel with asynchronous self power-off

In this paper we propose a second generation time-to-first-spike (TFS) pixel based on an asynchronous self power-off architecture. In this architecture time-to-first spike is used to encode the photocurrent information. Once the first spike is received and read-out using an address event representation (AER), the pixel is forced into standby mode by cutting off the power supply of itself. Simulation results shows that significant reduction in leakage power is achieved which is a major concern when implementing high resolution image sensor in deep-submicron technology. Based on this proposed architecture a prototype was designed in UMC 0.18 mum technology. Each pixel includes a photodiode, an event generator and hand-shaking communication protocol using 15 transistors. Each pixel occupies an area of 8.3 times 8.3mum² with a fill factor of 15%. In addition, the new generation TFS sensor features reduced depth of the arbitration tree using high-radix AER building block resulting in reduced overall delay