Triac Dimmer Detection Circuit Using Digital Signal Counting

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Solution Overview

Problem

Existing light emitting device driving circuits fail to accurately detect the degree of dimming in input AC power, leading to inadequate driving of light emitting devices in systems using Triac dimmers.

Innovation Solution

An illumination driving apparatus that includes a rectifying unit, a comparing unit, a reference voltage generating unit, and a PWM signal generating unit, which accurately detects the dimming degree of AC power by comparing the output waveform with a preset reference voltage and generating a PWM signal based on the detected high signals, ensuring compatibility with existing illumination fixtures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a scheme of detecting and averaging an output voltage of a Triac dimmer is used, then compatibility with existing illumination fixtures is achieved, but measurement precision of dimming degree deteriorates

Engineering Contradiction:

Improvecompatibility with existing illumination fixturesVSAvoiddimming degree detection accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces the conventional voltage averaging method with a digital signal processing approach using a microcontroller. The microcontroller counts the number of high-level signals in the rectified waveform to determine dimming degree, substituting analog averaging with digital measurement for improved precision while maintaining Triac dimmer compatibility.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a rectifying unit as an intermediary between the Triac dimmer output and the detection system. By rectifying the phase-controlled AC waveform before counting high-level signals, the system accurately captures the dimming degree information that would be lost in conventional averaging methods, enabling precise measurement while maintaining compatibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If conventional voltage averaging method is used, then device complexity is reduced, but measurement precision of dimming degree deteriorates

Engineering Contradiction:

Improvedetection circuit complexityVSAvoiddimming degree detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces complex analog averaging circuits with a simpler digital counting implementation using a microcontroller. The microcontroller's built-in timing and counting capabilities eliminate the need for complex analog signal processing, reducing overall device complexity while dramatically improving measurement precision through accurate high-level signal counting.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8779682B2Illumination driving apparatus

Publication Date: 2014.07.15 SKAICHIPS CO LTD

AI summary

A fixture-compatible, dimmable illumination driving apparatus including: a rectifying unit rectifying a phase-controlled waveform of an alternating current (AC) power; a comparing unit comparing an output waveform of the rectifying unit with a first voltage according to a preset reference clock; a reference voltage generating unit generating a reference voltage corresponding to the number of high signals higher than the first voltage among outputs of the comparing unit during one cycle of the output waveform; and a pulse width modulation (PWM) signal generating unit generating a PWM signal from the reference voltage and a feedback voltage.