Dimming Angle Sensing Circuit Using Zener Diode Voltage Comparison

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Solution Overview

Problem

Existing dimming angle sensing circuits face issues with size increase and switching noise, which affect the accuracy of dimming angle control in lighting systems, leading to undesired output current from power supplies.

Innovation Solution

A dimming angle sensing circuit utilizing a comparing circuit and a filtering circuit, which generates a comparison voltage based on line voltage and zener voltage, and an auxiliary voltage, respectively, to accurately sense the dimming angle without increasing the digital circuit size or causing switching noise, using zener diodes and resistors to clamp and filter voltages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a digital circuit is used to sense and calculate dimming angle, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improvedimming angle sensing accuracyVSAvoiddigital circuit size

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the digital circuit system with an analog circuit system. The dimming angle sensing is achieved through analog voltage comparison using a comparator, where the dimming angle information is converted to a voltage signal that can be directly compared with a reference voltage. This analog approach eliminates the need for complex digital processing circuits while maintaining sensing accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the parameter representation from digital values to analog voltage levels. The dimming angle is sensed as a voltage signal proportional to the angle, which is then compared with a reference voltage threshold. This parameter transformation simplifies the circuit by using continuous voltage signals instead of discrete digital values, reducing circuit complexity.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If a switch is used to sense dimming angle in digital circuit, then measurement precision is improved, but object-generated harmful factors increase due to switching noise

Engineering Contradiction:

Improvedimming angle sensing accuracyVSAvoidswitching noise

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent eliminates mechanical switching operations by using an analog voltage comparison approach. Instead of using switches to sample and digitize the dimming angle signal, the system continuously compares voltage levels representing the dimming angle with a reference voltage. This substitution of switching operations with continuous analog comparison removes the source of switching noise entirely.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If power supply increases switching duty to maintain output current, then productivity is maintained, but loss of energy increases

Engineering Contradiction:

Improveoutput current supplyVSAvoidswitching duty

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent implements a feedback mechanism where the dimming angle sensing circuit continuously monitors the actual dimming angle and provides this information to the power supply control. The power supply uses this feedback to adjust its output current dynamically, matching the required current level based on the actual dimming angle. This prevents the power supply from maintaining excessive switching duty when lower output current is sufficient, thereby reducing energy losses.

Inventive Principle:

Principle #23Feedback

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 allows for accurate dimming angle sensing without size increase or switching noise, enabling precise control of lighting brightness and reducing switching duty in power supplies, thereby improving the efficiency of the dimming process.

Implementation Method 1

a comparing circuit generating a comparison voltage according to a comparison result of a line voltage and a zener voltage

Methodology Applied

Scientific EffectZener breakdown: Avalanche Breakdown

Implementation Method 2

a filtering circuit generating a sense voltage corresponding to a dimming angle of the dimmer by low-pass filtering the comparison voltage

Methodology Applied

Scientific EffectCapacitive filtering: Capacitance

Implementation Method 3

the line voltage generated by rectifying an AC input passed through a dimmer

Methodology Applied

Scientific EffectRectification: Diode

Data Source

PatentUS8841850B2Dimming angle sensing circuit and driving method thereof

Publication Date: 2014.09.23 SEMICON COMPONENTS IND LLC

AI summary

The present invention relates to a dimming angle sensing circuit and a driving method thereof.A dimming angle sensing circuit according to an exemplary embodiment of the present invention uses a zener diode. The dimming angle sensing circuit generates a comparison voltage according to a comparison result of a line voltage and a zener voltage. The line voltage is generated from rectification of an AC input passed through a dimmer. The dimming angle sensing circuit generates a sense voltage corresponding to a dimming angle of the dimmer by low-pass filtering the comparison voltage.