Inductor Current Control Using Crossing-Time Regulation

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Solution Overview

Problem

Existing boost converter circuitry for portable electronic devices faces inefficiencies in regulating the current through an inductor during the charging phase, often requiring significant analogue components that occupy large silicon areas in integrated circuits, leading to increased costs and reduced manufacturing efficiency.

Innovation Solution

The implementation of control circuitry that includes comparison, detection, and current control mechanisms to monitor and adjust the inductor current based on a target average current, using digital and analogue circuitry to synchronize counters and generate control signals, thereby reducing the need for extensive analogue components and optimizing silicon area usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If significant analogue components are used to regulate inductor current during charging phase, then current regulation accuracy is improved, but silicon area occupied by control circuitry increases

Engineering Contradiction:

Improvecurrent regulation accuracyVSAvoidsilicon area

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent changes the control parameter from direct current magnitude regulation to timing-based regulation. By measuring the time duration of current flow through the inductor and comparing it to a reference time value, the system achieves current regulation accuracy without requiring complex analogue current sensing and regulation circuitry, thereby reducing silicon area while maintaining precision.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If extensive analogue circuitry is used for control, then control precision is improved, but manufacturing cost increases

Engineering Contradiction:

Improvecontrol precisionVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent substitutes extensive analogue circuitry with a hybrid digital-analogue approach using timing measurements. Instead of using complex analogue comparators and regulators, the system uses timers and counters to measure current flow duration, achieving comparable control precision with simpler, more manufacturable circuitry that reduces production costs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If more analogue components are used, then regulation accuracy is improved, but device complexity increases

Engineering Contradiction:

Improveregulation accuracyVSAvoidcircuitry complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transforms the regulation approach by changing from direct analogue parameter control to indirect timing-based control. The system measures the duration of inductor current flow and uses this time parameter to regulate current, significantly reducing circuit complexity while maintaining regulation accuracy through digital timing and counting mechanisms.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent extracts the essential regulation function from complex analogue circuitry and implements it through a simplified timing measurement mechanism. By taking out only the necessary timing and comparison functions and implementing them with simpler digital logic, the system achieves the same regulation accuracy with much lower circuit complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

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 solution effectively regulates the inductor current to match the target average current, reducing the silicon area occupied by the control circuitry and potentially increasing manufacturing efficiency and reducing production costs by minimizing the use of analogue circuitry.

Implementation Method 1

an increasing current IL flows through the inductor 110, as shown in the graph of FIG. 1. As a result of the increasing inductor current IL, the inductor stores some energy by generating a magnetic field.

Methodology Applied

Scientific EffectMagnetic field generation: Electromagnetic Induction

Implementation Method 2

The magnetic field around the inductor 110 collapses, inducing a flow of current which charges the reservoir capacitor 120.

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS11784565B2Control circuitry for controlling a current through an inductor of a power converter

Publication Date: 2023.10.10 CIRRUS LOGIC INC

AI summary

Control circuitry for controlling a current through an inductor of a power converter, the control circuitry comprising: comparison circuitry configured to compare a measurement signal, indicative of a current through the inductor during a charging phase of the power converter, to a signal indicative of a target average current through the inductor for the charging phase and to output a comparison signal based on said comparison; detection circuitry configured to detect, based on the comparison signal, a crossing time indicative of a time at which the current through the inductor during the charging phase is equal to the target average current for the charging phase; and current control circuitry configured to control a current through the inductor during a subsequent charging phase based on the crossing time.