LED Driving Apparatus with 180-Degree Phase Switching
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Solution Overview
Problem
Existing LED driving apparatuses that utilize AC power suffer from electromagnetic interference (EMI) issues when switching operations are controlled, leading to increased manufacturing costs and circuit area due to the need for separate EMI filters, which offsets the advantages of high efficiency and compact size offered by LEDs.
Innovation Solution
An apparatus that alternately switches pairs of LED units with a 180-degree phase difference, using a switching unit, current limiting unit, and driving control unit to manage switching based on rectified power voltage levels, eliminating the need for separate EMI filters by controlling the switching operations to suppress EMI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If switching operations are controlled in LED driving apparatuses using AC power, then LED units can be driven with rectified power, but electromagnetic interference (EMI) occurs due to the switching operation
Solution Approach 1:
The patent applies periodic action by alternately switching first and second LED units in response to periodic rectified power. The switching unit alternates between connecting the first LED unit and the second LED unit to the rectified power in a periodic manner, which reduces EMI while maintaining continuous light output.
Solution Approach 2:
The patent segments the LED driving system into multiple independent LED units (first LED unit, second LED unit) that are switched alternately. This segmentation allows the system to reduce EMI by not switching all LEDs simultaneously, while maintaining overall illumination through the alternating operation of segmented units.
2Object-generated harmful factors
If a separate EMI filter is adopted to solve EMI problems, then EMI can be reduced, but manufacturing costs and circuit area increase
Solution Approach 1:
The patent extracts and eliminates the need for separate EMI filters by integrating EMI reduction functionality directly into the switching control mechanism. The switching unit and control unit work together to reduce EMI through their operation, making external EMI filters unnecessary and thereby reducing circuit area and manufacturing cost.
Solution Approach 2:
The patent converts the potentially harmful switching operation that generates EMI into a beneficial EMI reduction mechanism. By alternating the switching of different LED units rather than switching all simultaneously, the system uses the switching action itself to reduce EMI, turning what was previously a harmful effect into a beneficial feature.
3Adaptability or versatility
If general AC-DC converter is used to drive LED with AC power, then LED can be driven with commercially available AC power, but volume and power consumption increase
Solution Approach 1:
The patent merges the AC-DC conversion function and LED driving function into a single integrated apparatus. The switching unit and control unit perform both rectified power management and LED driving control in one system, eliminating the need for separate AC-DC converter components and thereby reducing overall apparatus volume.
Solution Approach 2:
The patent creates a multi-functional apparatus where the switching unit and control unit serve multiple purposes: rectified power management, LED driving control, EMI reduction, and continuous illumination maintenance. This universality eliminates the need for dedicated separate components, reducing the overall volume of the driving apparatus.
Data Source
AI summary
There is provided an apparatus for driving a light emitting diode (LED), performing switching-operation with respect to a pair of LED groups by a phase difference of 180 degrees. The apparatus includes a switching unit that alternately switches a first LED unit and a second LED unit of at least one pair of LED units emitting light by receiving rectified power, in accordance with a predetermined phase difference, a current limiting unit that limits a current flowing in the at least one pair of LED units through the switching of the switching unit, and a driving control unit that controls switching driving of the switching unit in accordance with a voltage level of the rectified power.