LED Color Temperature Circuit Using One Optocoupler

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Solution Overview

Problem

Existing color temperature control systems for LEDs require multiple optocouplers to adjust color temperature, leading to high control costs, and there is a need for a cost-effective solution to simultaneously control multiple LED bead strings using a single optocoupler.

Innovation Solution

A color temperature control circuit utilizing a single optocoupler to control multiple LED bead strings through a signal input circuit, main control chip, and adjustment circuits with field-effect transistors and diodes, allowing simultaneous control of LED groups with different color temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If two independent optocouplers are used to control two LED bead strings separately, then color temperature adjustment is achieved, but control cost increases

Engineering Contradiction:

Improvecolor temperature adjustment capabilityVSAvoidcontrol cost

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the control functions of two independent optocouplers into a single optocoupler by cascading two adjustment circuits. The first adjustment circuit controls the first LED bead string, and its output feeds into the second adjustment circuit which controls the second LED bead string. This cascading structure allows one optocoupler to control multiple LED strings with different color temperatures, reducing component count and control cost while maintaining color temperature adjustment capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single optocoupler is designed to perform multiple functions: it controls both the first and second LED bead strings through the cascaded adjustment circuits. The first adjustment circuit handles the primary LED string while the second adjustment circuit handles the compensation LED string, allowing one optocoupler to replace what would traditionally require two separate optocouplers for independent control.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Device complexity

If a single optocoupler controls multiple LED bead strings, then control cost is reduced, but control precision may be affected

Engineering Contradiction:

Improvecontrol costVSAvoidcontrol precision

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The control function is segmented into two independent adjustment circuits that are cascaded together. The first adjustment circuit (with transistor Q1 and resistor R1) controls the first LED bead string, while the second adjustment circuit (with transistor Q2 and resistor R2) controls the second LED bead string. Each circuit can be independently adjusted to achieve precise control of its respective LED string, maintaining control precision despite using a single optocoupler.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first adjustment circuit acts as an intermediary between the optocoupler and the second adjustment circuit. The output signal from the first adjustment circuit feeds into the second adjustment circuit, allowing sequential control of multiple LED strings. This intermediary structure enables precise control by allowing independent adjustment of each circuit's parameters while maintaining overall system coordination.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Reduces control costs by enabling simultaneous control of multiple LED bead strings with different color temperatures using a single optocoupler, while providing power control through a dimming drive circuit.

Implementation Method 1

the first adjustment circuit includes a field-effect transistor Q1 and a first light-emitting bead group

Methodology Applied

Scientific EffectField-effect transistor control:

Implementation Method 2

the second adjustment circuit includes a field-effect transistor Q2 and a second light-emitting bead group

Methodology Applied

Scientific EffectField-effect transistor control:

Implementation Method 3

a signal is outputted to the optocoupler OP1 by the main control chip U1

Methodology Applied

Scientific EffectOptical coupling:

Implementation Method 4

a drain electrode of the field-effect transistor Q1 is connected to a gate electrode of the field-effect transistor Q2 through a diode D2

Methodology Applied

Scientific EffectDiode rectification: Diode

Data Source

PatentUS12532393B2Color temperature control circuit

Publication Date: 2026.01.20 JIANGMEN JIANGHAI HECHENG LIGHTING CO LTD

AI summary

The present disclosure is directed to a color temperature control circuit, including a signal input circuit, a main control chip U1, and a color temperature adjustment circuit. The color temperature adjustment circuit includes an optocoupler OP1, a first adjustment circuit, and a second adjustment circuit. The first adjustment circuit includes a field-effect transistor Q1 and a first light-emitting bead group; the second adjustment circuit includes a field-effect transistor Q2 and a second light-emitting bead group; color temperatures of the first and second light-emitting bead groups are different, a drain electrode of the field-effect transistor Q1 is connected to a gate electrode of the field-effect transistor Q2 through a diode D2. The main control chip U1 receives an input control signal, then outputs a signal to the optocoupler OP1, and controls a conduction of the field-effect transistors Q1 and Q2 through a high level and a low level, respectively.