LED Driver Dimming Mode Detection via Voltage Timing
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Solution Overview
Problem
Existing LED driving apparatuses face challenges in detecting dimming modes, particularly leading edge, trailing edge, and no dimming conditions, leading to performance issues and flicker, due to the complexity and high cost of existing digital solutions.
Innovation Solution
A dimming mode detection method that includes a rectifier bridge, bus capacitor, bleeding circuit, and switching converter, utilizing voltage sensing signals to differentiate between dimming modes by comparing rising and falling times with threshold voltages and times, generating appropriate control signals to manage the LED driving apparatus's operation modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If digital technology is used for dimming mode detection, then detection accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex digital detection circuits with an analog-based solution using a timing circuit that measures the duration of voltage signals from the dimmer. This analog timing approach substitutes for digital signal processing, achieving accurate dimming mode detection while significantly reducing device complexity and cost.
Solution Approach 2:
The patent employs simple, low-cost analog components (comparators, timing circuits, resistors, capacitors) instead of expensive digital detection circuits. These simple components achieve the detection function effectively, aligning with the principle of using cheap, simple elements to solve the problem.
2Measurement precision
If digital technology is used for dimming mode detection, then detection accuracy is improved, but cost increases
Solution Approach 1:
The patent employs simple, low-cost analog components (comparators, timing circuits, resistors, capacitors) instead of expensive digital detection circuits. These simple components achieve the detection function effectively, aligning with the principle of using cheap, simple elements to solve the problem.
Solution Approach 2:
The patent replaces complex digital detection circuits with an analog-based solution using a timing circuit that measures the duration of voltage signals from the dimmer. This analog timing approach substitutes for digital signal processing, achieving accurate dimming mode detection while significantly reducing device complexity and cost.
3Device complexity
If the LED driving apparatus does not distinguish dimming conditions, then device simplicity is maintained, but performance deteriorates and flicker occurs
Solution Approach 1:
The patent replaces complex digital detection circuits with an analog-based solution using a timing circuit that measures the duration of voltage signals from the dimmer. This analog timing approach substitutes for digital signal processing, achieving accurate dimming mode detection while significantly reducing device complexity and cost.
Solution Approach 2:
The patent segments the detection process into distinct time-based measurements: measuring the duration of the first voltage signal to detect leading edge dimming, and measuring the duration of the second voltage signal to detect trailing edge dimming. This segmentation allows the simple timing circuit to reliably distinguish between different dimming modes and select appropriate operating modes, preventing flicker and performance issues.
Data Source
AI summary
A dimming mode detection method is used in an LED driving apparatus including a rectifier bridge providing a DC bus voltage and a switching converter configured to convert the DC bus voltage into a driving signal to drive an LED. The method involves: powering on the LED driving apparatus; sensing the DC bus voltage and generating a voltage sensing signal; comparing a rising time during which the voltage sensing signal increases from a second threshold voltage to a first threshold voltage with a first time threshold to detect whether the LED driving apparatus is connected to a leading edge dimmer; and comparing a falling time during which the voltage sensing signal decreases from a third threshold voltage to a fourth threshold voltage with a second time threshold to detect whether the LED driving apparatus is connected to a trailing edge dimmer.