LED Driving Circuit Harmonic Distortion Reduction
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Solution Overview
Problem
Conventional LED driving circuits with low-order linear constant current circuits suffer from harmonic distortion, necessitating the use of costly and area-intensive multi-order linear constant current circuits to mitigate this issue.
Innovation Solution
Incorporating a rectifying circuit, a linear constant current circuit, a current limiting circuit, and a current limiting ramp slope determining circuit to generate a current limiting effect and determine the ramp slope, thereby reducing harmonic distortion without the need for high-order linear constant current circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a multi-order (over fifth-order) linear constant current circuit is used to reduce harmonic distortion, then the harmonic distortion is reduced, but the cost and circuit area increase significantly
Solution Approach 1:
The patent changes the operating parameters of the linear constant current circuit by introducing a current limiting circuit with adjustable current limiting height and a current limiting ramp slope determining circuit. These parameter adjustments optimize the circuit operation to reduce harmonic distortion without requiring a multi-order circuit architecture
Solution Approach 2:
The patent introduces a current limiting circuit as an intermediary component between the rectifying circuit and the linear constant current circuit. This intermediary circuit, controlled by the ramp slope determining circuit, mediates the current flow to reduce harmonic distortion while keeping the main linear constant current circuit at a lower order
2Object-generated harmful factors
If a multi-order (over fifth-order) linear constant current circuit is used to reduce harmonic distortion, then the harmonic distortion is reduced, but the cost increases
Solution Approach 1:
By adjusting the parameters of the current limiting circuit and ramp slope determining circuit, the patent achieves reduced harmonic distortion with a lower-order linear constant current circuit, thereby reducing manufacturing cost while maintaining performance
Solution Approach 2:
The patent replaces the expensive multi-order linear constant current circuit with a combination of a low-order linear constant current circuit and simple current limiting components, achieving cost reduction while maintaining the harmonic distortion reduction effect
Data Source
AI summary
The present invention provides a light emitting diode (LED) driving circuit with low harmonic distortion. The LED driving circuit comprises: a rectifying circuit, a linear constant current circuit, a current limiting circuit, and a current limiting ramp slope determining circuit. The rectifying circuit is utilized for rectifying an alternating current (AC) power source to provide a direct current (DC) voltage output. The linear constant current circuit is utilized for driving at least an LED. The current limiting circuit is connected in parallel between the rectifying circuit and the linear constant current circuit, and utilized for generating a current limiting effect and determining a current limiting height. The current limiting ramp slope determining circuit is connected in parallel between the rectifying circuit and the linear constant current circuit and connected in series with the current limiting circuit, and utilized for determining a current limiting ramp slope.