LED Controller Inductor Voltage Sensing for Constant Current Regulation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional LED lamp control methods require separate components for current and voltage regulation, leading to power loss and increased system complexity, as well as higher costs due to the use of current transformers and output current sensing resistors.

Innovation Solution

An LED controller that senses inductor voltage to determine the inductor reset time and generates a control signal to regulate the switching period and on-time of a switch, allowing for constant current regulation without the need for output current sense resistors or current transformers, thereby reducing power loss and system complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an output current sensing resistor is used to regulate current for LED lamps, then current regulation is achieved, but power loss increases

Engineering Contradiction:

Improvecurrent regulationVSAvoidpower loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent extracts the current sensing function from the traditional output current sensing resistor and relocates it to the inductor voltage sensing point. By measuring the inductor voltage during the reset phase, the system derives current information without requiring a separate sensing resistor in the output path, thereby eliminating the power loss associated with output current sensing.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces inductor voltage as an intermediary measurement parameter. Instead of directly sensing output current through a resistor, the system uses the inductor voltage waveform (specifically the reset time) as an indirect but accurate indicator of output current, which then feeds back to control the switching element and achieve current regulation without the intermediary sensing resistor causing power loss.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a current transformer is used to monitor current for LED lamps, then current sensing is achieved, but system cost increases

Engineering Contradiction:

Improvecurrent sensingVSAvoidsystem cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent removes the current transformer from the system entirely and extracts the current sensing capability from a separate component into the inductor itself. The inductor's inherent voltage characteristics during reset provide the current information that would otherwise require an expensive current transformer, significantly reducing system cost while maintaining sensing accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a functional copy of the current sensing capability using the inductor voltage waveform instead of physically copying the current through a transformer. By measuring the inductor voltage during the reset phase and deriving current information from the reset time, the system replicates the current sensing function without the cost and complexity of a current transformer.

Inventive Principle:

Principle #26Copying

3Reliability

If separate components are used to monitor current and voltage for LED protection, then protection functionality is achieved, but device complexity increases

Engineering Contradiction:

Improveprotection functionalityVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the current sensing, voltage monitoring, and protection functions into a single integrated approach. By sensing the inductor voltage (which inherently contains both current and voltage information) and using the reset time as a combined indicator, the system eliminates the need for separate current sensing resistors, voltage dividers, and protection circuits, thereby reducing device complexity while maintaining comprehensive protection functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The inductor voltage sensing point serves multiple functions simultaneously: it provides current information through reset time measurement, monitors output voltage levels, and enables protection functionality. This multi-functional use of a single sensing point eliminates the need for separate dedicated components for each function, significantly reducing system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 enables efficient constant current regulation for LED lamps, reducing power loss and system complexity while lowering costs by eliminating the need for additional sensing components, thus providing a more effective and cost-efficient LED lamp control method.

Implementation Method 1

The LED controller senses an inductor voltage and determines an inductor reset time from the sensed inductor voltage

Methodology Applied

Scientific EffectElectrical voltage sensing: Electric Field

Data Source

PatentUS9420645B2Constant current control buck converter without current sense

Publication Date: 2016.08.16 DIALOG SEMICONDUCTOR INC

AI summary

A light emitting diode (LED) controller provides constant current regulation for a converter circuit providing current to an LED. The LED controller senses an inductor voltage and determines an inductor reset time from the sensed inductor voltage. Based on the determined inductor reset time, a switch on time and a switch period, the LED controller generates a control signal modifying the state of a switch coupling the converter circuit to an input voltage.