A Novel ΔΣ Control System Processor and Its VLSI Implementation

This paper describes a novel control system processor architecture based on ΔΣ modulation known as the ΔΣ-CSP. The ΔΣ-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 ΔΣ-CSP configurations have been implemented as VLSI hard macros in a high-performance 0.13-μm 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 ΔΣ-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.