LED Switching Regulator Controller for Average Current Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional switching regulators in LED lighting systems face challenges in accurately controlling the average LED current due to delay issues, inductance, and voltage ratios, leading to deviations from desired current values, which complicates the control of light intensity and increases hardware costs.

Innovation Solution

A controller for the switching regulator comprising a current monitor, voltage divider, integration circuit, and comparator circuit is used to sense LED current, generate divided voltages, and compare them with a reference voltage to generate a driving signal, thereby compensating for delays and voltage influences, ensuring the actual average LED current aligns with the desired value.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional switching regulator with logic gate and gate driver is used, then the regulator can provide current to LED, but delay issue occurs and average LED current cannot be controlled easily

Engineering Contradiction:

Improvecontrol of average LED currentVSAvoiddelay in logic gate and gate driver

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The patent replaces the conventional logic gate and gate driver circuitry with a current mirror circuit that directly replicates the reference current waveform. This substitution eliminates the timing delays inherent in logic gates and gate drivers by using a direct current replication mechanism, thereby improving the controllability of average LED current without time loss.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If inductor with certain inductance is used in switching regulator, then the regulator can function, but the inductance affects the control of average LED current

Engineering Contradiction:

Improvecontrol of average LED currentVSAvoidinfluence of inductance on current control

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent employs a feedback mechanism where the current mirror continuously monitors and replicates the reference current, compensating for variations caused by inductor characteristics. This feedback approach allows the system to maintain accurate average current control despite the presence of inductance effects in the switching regulator circuit.

Inventive Principle:

Principle #23Feedback

3Power

If voltage ratio of input voltage and output voltage is adjusted, then the regulator output can be controlled, but it affects the control of average LED current

Engineering Contradiction:

Improveregulator output voltageVSAvoidcontrol of average LED current

Core Design Contradiction:

PowerVSEase of operation

Solution Approach 1:

The patent segments the current control function from the voltage regulation function. By using a separate current mirror circuit that directly replicates the reference current waveform, the system decouples current control from voltage ratio adjustments, allowing independent optimization of both power output and average LED current control without mutual interference.

Inventive Principle:

Principle #1Segmentation

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

The proposed solution effectively reduces non-ideal effects on the average LED current, ensuring it matches the desired value, independent of logic circuit delays, inductance, input/output voltage ratios, and LED forward voltage, thus improving light intensity control without increasing hardware complexity.

Implementation Method 1

The current monitor is used to sense a LED current passing through a current sensing resistor of the switching regulator, and to generate a sensing current

Methodology Applied

Scientific EffectOhm's Law: Ohm's Law

Implementation Method 2

The voltage divider is connected to the current monitor, and used to receive the sensing current to generate a first through third divided voltages

Methodology Applied

Scientific EffectCurrent Division: Ohm's Law

Implementation Method 3

The integration circuit is connected to the voltage divider, and used to compare the second divided voltage with a reference voltage, and to generate an integration voltage across a RC circuit thereof accordingly

Methodology Applied

Scientific EffectRC Integration: Capacitance

Data Source

PatentUS10462860B2Controller for switching regulator, switching regulator and LED lighting system

Publication Date: 2019.10.29 ELITE SEMICONDUCTOR MEMORY TECHNOLOGY INC

AI summary

A controller for a switching regulator of a LED lighting system has a current monitor, a voltage divider, an integration circuit, and a comparator circuit. The current monitor is used to sense a LED current passing through a current sensing resistor of the switching regulator, and to generate a sensing current. The voltage divider is used to receive the sensing current to generate a first through third divided voltages, wherein the first divided voltage is larger than the second divided voltage, and the second divided voltage is larger than the third divided voltage. The integration circuit is used to compare the second divided voltage with a reference voltage, and to generate an integration voltage across a RC circuit thereof accordingly. The comparator circuit is used to compare the integration voltage with the first divided voltage and the third divided voltage, and to generate a driving signal.