Distributed Voltage Averaging for Accurate Total Current Sensing

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Solution Overview

Problem

Accurately measuring current in integrated circuits (ICs) is challenging due to varying voltage and current profiles across distributed load circuit elements, leading to inaccurate current control and potential circuit failures.

Innovation Solution

A current sense circuit using distributed voltage averaging, which determines average voltages across multiple resistive paths in a distribution network to calculate the total current independently of current distribution, allowing for more accurate measurement and control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If current is measured in one particular area of an IC, then the measurement is simple and localized, but the current measurement does not provide an accurate representation of overall current within the IC

Engineering Contradiction:
Improvecurrent measurement accuracyVSAvoidcurrent sense circuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The distribution network is segmented into multiple resistive paths, each monitored by its own voltage averaging circuit. This segmentation allows the system to capture current information from different regions of the IC independently, then combine these measurements to achieve accurate overall current measurement without requiring a single complex measurement point.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Voltage averaging circuits serve as intermediary elements that convert difficult-to-measure current distributions into measurable voltage differences. By measuring voltage across resistive paths and averaging them, the system obtains an indirect but accurate representation of total current, avoiding the need for direct current measurement in complex distributed circuits.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If voltage scaling is slowed and active components per unit area are increased, then IC functionality and performance are improved, but excessive current causes circuit failure

Engineering Contradiction:
Improveactive components per unit areaVSAvoidcircuit failure prevention
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The current sense circuit provides continuous feedback about total current consumption to the control system. When the measured current approaches dangerous levels, the control system can adjust operational parameters to reduce current draw, preventing circuit failure while allowing maximum component density to be utilized safely.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary current measurement and evaluation before excessive current can cause damage. By continuously monitoring current through the voltage averaging method and establishing threshold levels in advance, the control system can take preventive action before circuit failure occurs, enabling higher component density operation.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach provides a more accurate measurement of total current, enhancing the effectiveness of control systems in preventing circuit failures caused by excessive current.

Implementation Method 1

a plurality of resistive circuits (114(1)-114(N), 124(1)-124(N)) Each resistive circuit also comprises an output node (120(1)-120(N), 130(1)-130(N)) electrically coupled to a voltage output node (122, 132) having an average voltage (V AVG1, V AVG2)

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

The current sense circuit also includes an amplifier (134) with an output node (138) having an output voltage (V OUT) that correlates to a difference of the average voltages multiplied by a gain of the amplifier (134)

Methodology Applied
Scientific EffectElectrical Amplification:

Data Source

PatentEP3665488B1Sensing total current of distributed load circuits independent of current distribution using distributed voltage averaging
Publication Date: 2023.04.19 QUALCOMM INC
  • EP3665488B1 patent drawingFigure 1
  • EP3665488B1 patent drawingFigure 2
  • EP3665488B1 patent drawingFigure 3A

AI summary

Aspects for sensing total current of distributed load circuits (102) independently of a spatial profile of the total current using distributed voltage averaging are disclosed. In one aspect, a current sense circuit (100) is configured to sense total current of a distributed load circuit independently of where current is distributed. The current sense circuit includes distributed voltage averaging circuits (112(1), 112(2)) configured to determine average voltages of the distributed load circuit based on voltages sensed at multiple resistive paths (108(1) -108(N)) corresponding to a distribution network configured to provide voltage to the distributed load circuit. An amplifier (134) includes an output node having an output voltage (VOUT) that is proportional to total current flowing in the distributed load circuit. The current sense circuit allows for sensing total current independent of where the current flows, providing more accurate current sensing compared to sensing current in one area of the distributed load circuit.