A Novel ΣΔ Control Stystem Processor and its VLSI implementation

This paper describes a novel control system processor architecture based on $DeltaSigma$ modulation known as the $DeltaSigma$-CSP. The $DeltaSigma$-CSP utilizes 1-bit processing which is a new concept in digital control applications with the direct benefit of making multi-bit multiplication operations redundant. A simple conditional-negate-and-add (CNA) unit is instead used for operations in control law implementations. For this reason, the proposed processor has a very small silicon footprint and runs at very high frequencies making it ideal for high-sampling rate, real-time control applications. A number of $DeltaSigma$-CSP configurations have been implemented as VLSI hard macros in a high-performance 0.13-$mu$m CMOS process and a particular configuration achieved a post-route operating frequency of 355 MHz resulting in a 2.17 MHz sampling rate for a fourth-order control law implementation. Additional results prove that the $DeltaSigma$ -CSP compares very favorably, in terms of silicon area and sampling rates, to two other specialized digital control processing systems, including direct, hardwired implementation of control laws; at the same time, it substantially outperforms software implementations of control laws running on very wide, general-purpose VLIW architectures.