Application Specific Integrated Data Processing in ADCs for High Accuracy, Low Latency Advanced Real Time Control Systems

Advanced real time control systems re-quire low latency, high accuracy digital signal processing to address the needs of the new and emerging end equipment. Conventionally, processing is implemented in software leading to additional MIPS (Million instructions Per Second) consumption and lower accuracy. These systems also have sampling of real-world signals as one of the important steps. This is typically done using Analog-to-Digital Converters (ADCs). As accuracy and latency requirements have become more stringent, central processing of the ADC output is also becoming a bottleneck, requiring the first level of ADC processing to be brought closer to the module. This paper proposes novel techniques like sample rate modulation, accumu-lation, limit compare and post-processing to augment conventional ADC processing, improving accuracy and reducing latency. In addition to the control processing demands, functional safety requirements are also increasing. Functional safety diagnostic logic deployed in hardware offers the additional benefits of lower la-tency (thus impacting the Fault-Tolerant Time Interval (FTTI)) and lower deployment effort. The techniques proposed in this paper helped to reduce MIPS by up to 15%, enabled up to 15 times faster fault detection and provided effective number of bits (ENOB) gain of up to 2 bits. The safety checker logic implemented in this system helped achieve system-level ASIL-D with much smaller software overhead compared to conventional systems.