Compute-in-Memory Flip-Flop Suspension for All-Zero Inputs

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Solution Overview

Problem

Existing compute-in-memory (CIM) systems consume excessive energy when all bits of a data signal are logical zero due to unnecessary propagation through leader-follower flip-flops (L/F FFs), leading to inefficiencies in power consumption.

Innovation Solution

Incorporating a suspender unit and nulling logic to detect when all bits of a data signal are zero, suppressing latching and generating a zero product signal without propagating through the L/F FFs, thereby reducing energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If data propagation through leader-follower flip-flops is performed in conventional CIM systems, then data processing functionality is maintained, but energy consumption increases unnecessarily when all bits are zero

Engineering Contradiction:

Improveenergy consumptionVSAvoidsystem complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The suspender unit performs preliminary detection of the all-zero condition in the data signal before the data propagates through the leader-follower flip-flops. By detecting this condition in advance and generating a nulling signal, the system prevents unnecessary latching operations and multiplication operations, thereby reducing energy consumption while maintaining functional correctness

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention extracts and handles the all-zero case as a special condition separate from normal data processing. The suspender unit isolates this specific scenario and applies a simplified handling mechanism (generating a nulling signal that forces zero outputs) instead of proceeding with the full data propagation through L/F FFs, thus eliminating wasted energy on unnecessary operations

Inventive Principle:

Principle #2Taking out (Extraction)

2Productivity

If latching operations are performed by leader-follower flip-flops for every clock cycle, then data signal processing is continuous, but power consumption increases due to unnecessary operations when data is all zeros

Engineering Contradiction:

Improvedata processing throughputVSAvoidpower consumption

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The system dynamically adjusts its operation based on the input data condition. The suspender unit monitors the data signal and dynamically controls the clock signals to the leader-follower flip-flops: when all bits are zero, clock signals are suppressed to prevent unnecessary latching operations; when non-zero data is detected, normal clocking resumes. This dynamic adaptation maintains productivity while reducing energy loss

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12587175B2Reduced power consumption compute-in-memory system, method of operating same

Publication Date: 2026.03.24 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A compute-in-memory (CIM) system includes a first leader-follower (L/F) flip-flop (FF), a suspender unit and a multiplication unit. The first L/F FF is configured to receive a data signal. The first L/F FF includes: a first leader FF configured to receive the data signal and a first follower FF configured to generate a signal first_Q_follow that represents a output signal of the first L/F FF. The multiplication unit is configured to receive a weight signal W and the signal first_Q_follow and generate a first product signal. The suspender unit is configured, during a given cycle of the first clock signal, detect that a first scenario is true in which all bits b(k) of the data signal equal logical zero and accordingly suppress latching from being performed by the first L/F FF, and control the multiplication unit to generate the first product signal as being equal to logical zero.