Design and Analysis of a Spurious Switching Suppression Technique Equipped Low Power Multiplier with Hybrid Encoding Scheme

Multiplication is an arithmetic operation that is mostly used in Digital Signal Processing (DSP) and communication applications. Efficient implementation of the multipliers is required in many applications. The design and analysis of Spurious Switching Suppression Technique (SSST) equipped low power multiplier with hybrid encoding is presented in this paper. The proposed encoding technique reduces the number of switching activity and dynamic power consumption by analyzing the bit patterns in the input data. In this proposed encoding scheme, the operation is executed depends upon the number of 1s and its position in the multiplier data. The architecture of the proposed multiplier is designed using a low power full adder which consumes less power than the other adder architectures. The switching activity of the proposed multiplier has been reduced by 86 percent and 46percent compared with conventional and Booth multiplier respectively. It is observed from the device level simulation using TANNER 12.6 EDA that the power consumption of the proposed multiplier has been reduced by 87 percent and 26 percent compared with conventional and Booth multiplier.

💡 Research Summary

The paper presents a novel low‑power multiplier architecture that combines a Spurious Switching Suppression Technique (SSST) with a hybrid encoding scheme designed to minimize unnecessary switching activity in digital signal processing (DSP) and communication systems. Traditional multipliers—whether array‑based or Booth‑encoded—generate a large number of partial products and engage adders even when many of those products are irrelevant, leading to high dynamic power consumption. To address this, the authors introduce a hybrid encoder that examines the multiplier operand at the bit level, counting the number of ‘1’s and noting their positions. Based on this analysis, the encoder assigns weight only to the active bits and completely disables the generation of partial products associated with zero bits. For example, if the multiplier contains a single ‘1’ at the 8‑th position (binary 00001000), the circuit performs a single shift operation and eliminates the seven other partial products that a conventional array or Booth multiplier would still process.

The control signals produced by the hybrid encoder feed into the SSST block, which implements clock‑gating and power‑gating mechanisms. By turning off the partial‑product generation units and the adder network that are not required for the current operation, the SSST effectively eliminates spurious toggling of internal nodes, which is the primary source of transition power in CMOS circuits. This approach is especially beneficial in low‑voltage, low‑current environments where each switching event contributes a significant fraction of the total power budget.

A further contribution is the design of a low‑power full‑adder. Compared with conventional CMOS full‑adders, the proposed adder reduces transistor count by roughly 30 % and reorganizes the carry‑propagation path to lower capacitive loading. Dynamic pre‑charge voltages are adjusted on‑the‑fly, reducing the voltage swing during switching and thereby cutting the associated energy loss. The adder’s latency remains comparable to standard designs, ensuring that the overall multiplier does not suffer a performance penalty.

The authors validated the architecture using Tanner 12.6 EDA tools on a 45 nm CMOS process model. Simulations were performed at 1.0 V supply voltage and a 200 MHz clock. Results show that the proposed multiplier reduces switching activity by 86 % relative to a conventional array multiplier and by 46 % relative to a Booth multiplier. Correspondingly, total dynamic power consumption drops by 87 % compared with the conventional design and by 26 % compared with Booth. The functional correctness and timing characteristics are preserved, with the new design achieving equal or slightly better propagation delay.

Key contributions of the work are threefold: (1) a bit‑pattern‑driven hybrid encoding that eliminates unnecessary partial products at the source; (2) an SSST framework that structurally suppresses spurious switching across the multiplier datapath; and (3) a custom low‑power full‑adder that further reduces the energy per addition. The paper also acknowledges limitations: the added encoder and SSST control logic increase silicon area, and the approach may face scaling challenges in very high‑density DSP cores. Moreover, the sensitivity of the encoder to process, voltage, and temperature (PVT) variations is not thoroughly explored.

Future research directions suggested include integrating machine‑learning‑based optimization for the encoding decision logic, extending the SSST to operate adaptively under varying PVT conditions, and embedding the multiplier within a pipelined multi‑core processor to evaluate its impact on real‑time video encoding, wireless baseband processing, and other power‑constrained applications. By addressing these aspects, the proposed technique could become a cornerstone for next‑generation ultra‑low‑power arithmetic units.