Series LED Lamp with PWM Signal Controller
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Solution Overview
Problem
High-resolution LED headlamps require numerous power supply devices, leading to increased material costs and circuit board area, with issues of current differences and connector pin counts when LED columns are connected in parallel, and output limitations when connected in series.
Innovation Solution
A lamp design with light sources connected in series, featuring a light source controller and signal controller that manage duty cycles to prevent operating voltage exceedance, optimize current flow, and adjust power distribution based on vehicle-related information, reducing the number of power supply devices and preventing overvoltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If many power supply devices are provided to supply power to a plurality of high-resolution LEDs, then power supply reliability is improved, but material cost and circuit board area increase
Solution Approach 1:
The patent combines multiple power supply functions into a single power supply device by connecting LED columns in series. This single power supply device can control multiple LED columns sequentially through pulse width modulation (PWM) signals, eliminating the need for multiple separate power supply devices and reducing both material cost and circuit board area while maintaining reliable power supply to all LEDs
Solution Approach 2:
The patent employs periodic PWM signals to control the timing of LED column operation. By sequentially activating different LED columns during different time periods within a cycle, the single power supply device can efficiently manage power distribution to multiple LED columns without requiring simultaneous power supply circuits for each column
2Adaptability or versatility
If LED columns are connected in parallel, then power supply flexibility is improved, but current difference and connector pin count increase
Solution Approach 1:
Instead of connecting LED columns in parallel as conventionally done, the patent inverts the connection approach by connecting LED columns in series. This inversion eliminates the current difference problem inherent in parallel connections, as the same current flows through all series-connected columns, while also reducing the number of connector pins required
3Quantity of substance
If LED columns are connected in series, then material cost and circuit board area are reduced, but output voltage limit is exceeded
Solution Approach 1:
The patent uses periodic PWM control to manage the series-connected LED columns. By activating columns sequentially rather than simultaneously, the peak voltage requirements are reduced, allowing the system to operate within the power supply's output voltage limits while maintaining series connection benefits of reduced material cost and circuit board area
Solution Approach 2:
The patent implements dynamic control of LED column operation through PWM signaling. The power supply device can adjust the duty cycle and timing of each LED column's activation dynamically, optimizing voltage and current distribution across the series-connected columns to prevent exceeding output voltage limits while maintaining efficient operation
Data Source
AI summary
According to an embodiment disclosed herein, a lamp includes a plurality of light sources connected in series to one another, a light source controller that controls an operation of each of the plurality of light sources based on a control signal, and a signal controller that generates the control signal containing a duty cycle set such that an operating voltage of the plurality of light sources does not exceed a preset value and controls an operation of the light source controller in a time division manner.