Opto-Electric Analog SRAM Device Based on Commercial LEDs and Photodetectors

In this paper, we propose an opto-electric analog static random-access memory (OE-ASRAM) structure consisting of two opto-electric inverters as a flip-flop circuit. The opto-electric inverter is constructed as a photosensor-based inverter with a light-emitting diode (LED), such as a light generator, considered as an input analog signal, and is transmitted to a photosensor for generating an output voltage, considered as a digital signal. This operates as an inverter and can be considered as an analog-to-digital converter (ADC). By adding metal-oxide-semiconductor field-effect transistor (MOSFET) (current switch) and second LED (output photo signal generator), we can convert the digital signal (electric) to an analog signal (photo) as a digital-to-analog converter (DAC). By constructing two opto-electric inverters as a flip-flop structure, we achieve an OE-ASRAM circuit that works as a common SRAM that can store 1-bit data from both analog (photo) and digital signals. In this paper, we present the operation characteristics of the opto-electric inverter, as well as the proposed OE-ASRAM circuit with two uncommon access methods of mechanical screening and laser lighting. The proposed OE-ASRAM structure can be used as the basic building structure for mixed signal processors that can store data for both analog (photo) and digital inputs.