Dynamic-Precision Processing Circuit Without Level Shifters

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Solution Overview

Problem

Existing dynamic voltage accuracy scaling (DVAS) systems face limitations such as the 'Wall-of-Slack' phenomenon, where timing violations occur due to optimization of short paths for power and area, and the complexity and power consumption added by requiring level shifters for different supply voltages across the circuit.

Innovation Solution

A processing circuit with multiple circuit domains, each with independently adjustable transistor biasing voltages, controlled by a dynamic accuracy control circuit that determines voltage settings based on selected accuracy, supply voltage, and frequency settings, allowing for dynamic modification of accuracy while avoiding timing violations and reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If DVAS reduces supply voltage to lower power consumption, then power consumption is reduced, but timing violations occur due to the 'Wall-of-Slack' phenomenon

Engineering Contradiction:
Improvepower consumptionVSAvoidtiming compliance
Core Design Contradiction:
Use of energy by stationary objectVSReliability

Solution Approach 1:

The circuit is divided into multiple circuit domains, each with independently controllable biasing voltages. This segmentation allows selective performance boosting in critical paths without affecting the entire circuit, enabling voltage scaling while maintaining timing compliance in segmented regions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different circuit domains are assigned different biasing voltage levels based on their specific timing requirements. Critical paths receive higher biasing voltages to maintain speed, while non-critical paths operate at lower voltages for power savings, creating local quality variations that resolve the timing-power contradiction.

Inventive Principle:
Principle #3Local quality

2Productivity

If DVAS uses different supply voltages for different circuit parts to optimize performance, then performance is improved, but level shifters are required adding complexity and power consumption

Engineering Contradiction:
ImproveperformanceVSAvoidcircuit complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Instead of changing supply voltage levels across different circuit parts, the invention changes the biasing voltage parameter of transistors while maintaining a common supply voltage. This parameter change approach achieves performance differentiation without requiring level shifters, reducing circuit complexity.

Inventive Principle:
Principle #35Parameter changes

3Speed

If bit width is reduced to relax operating conditions and increase frequency, then operating frequency can be increased, but accuracy is reduced

Engineering Contradiction:
Improveoperating frequencyVSAvoidaccuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The circuit enables dynamic adjustment of biasing voltages based on operational requirements. During high-accuracy operations, higher biasing voltages are applied to maintain precision; during low-accuracy modes, lower biasing voltages reduce power consumption while maintaining adequate frequency, creating a dynamic trade-off mechanism.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3379406B1Processing circuit capable of dynamically modifying its precision
Publication Date: 2019.06.05 POLITECNICO DI TORINO
  • EP3379406B1 patent drawingFigure 1~2
  • EP3379406B1 patent drawingFigure 3~6
  • EP3379406B1 patent drawingFigure 4~7

AI summary

The invention concerns a circuit comprising: a processing circuit (102) comprising a plurality of circuit domains (103), each circuit domain (103) comprising a plurality of transistors and being configured to apply one or more corresponding transistor biasing voltages to said transistors; and a control circuit (104) configured to determine, based on at least a selected accuracy setting of the processing circuit, the level of said one or more transistor biasing voltages to be applied in each of said circuit domains, the control circuit (104) being further configured to cause said transistor biasing voltages to be applied to the circuit domains.