Vehicle Lighting Circuit with Shared Conversion Unit for Turn Signal and DRL
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Solution Overview
Problem
Existing lighting circuits for vehicles, particularly those combining turn signal lamps and daytime running lamps (DRL), face challenges in efficient light emission management when light sources are closely arranged, leading to potential detection errors and visibility issues due to unstable current and simultaneous light activation.
Innovation Solution
A lighting circuit configuration that uses a common conversion unit and control unit for both light sources, with switches to manage voltage supply and generate signals for selective light emission, preventing detection errors and ensuring appropriate light emission by prioritizing one light source over the other based on voltage supply states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the DRL light source and turn light source are arranged closely or share common light emission surfaces, then the vehicle width indication and visibility are improved, but detection errors occur due to unstable input current to the conversion unit
Solution Approach 1:
The patent divides the input current path into separate segments by introducing third switch 37 that selectively connects either first voltage Vtn or second voltage Vdr to the conversion unit 31. This segmentation prevents the mixing of currents from different voltage sources, ensuring stable current detection for each lighting mode and eliminating detection errors.
Solution Approach 2:
The third switch 37 acts as an intermediary component between the voltage sources and the conversion unit. It mediates the connection by selectively allowing only one voltage source to supply current to the conversion unit at a time, thereby preventing current instability and detection errors while maintaining the ability to switch between different lighting functions.
2Ease of operation
If separate DC/DC converters and control circuits are provided for DRL and turn signal lamp, then each light source can be controlled independently, but the device complexity and cost increase
Solution Approach 1:
The conversion unit 31 and control unit 32 are designed as universal components that can serve multiple functions. The conversion unit can convert either first voltage Vtn or second voltage Vdr to the appropriate driving voltage, and the control unit can control both the turn light source 3 and DRL light source 4. This multi-functionality reduces component count and complexity while maintaining independent control capability through the first switch 39tn and second switch 39dr.
Solution Approach 2:
The patent merges the DC/DC conversion function and control function into shared units that serve both lighting systems. By combining these functions, the overall system complexity is reduced while the first switch 39tn and second switch 39dr maintain the ability to independently control each light source based on their respective voltage inputs.
3Illumination intensity
If the DRL is turned off during turn signal blinking, then the turn signal visibility is maintained, but the light emission continuity is reduced
Solution Approach 1:
The system dynamically adjusts the operation of each light source based on the active function. When turn signal function is active, the DRL is controlled to remain off during blinking periods to maintain turn signal visibility. When DRL function is active, the turn signal can operate normally. This dynamic adjustment is achieved through the control unit 32 receiving voltage inputs and controlling the respective switches to prioritize the appropriate light source based on the current operational mode.
Data Source
AI summary
A lighting circuit is configured to supply a driving current to a first light source and a second light source. The light circuit includes a conversion unit which receives a first voltage for the first light source and a second voltage for the second light source via a common input terminal, performs voltage conversion on the first voltage or the second voltage and supplies the driving current, a control unit which controls a current value of the driving current output from the conversion unit, a first switch which selects whether to supply the driving current to the first light source by a first signal based on the first voltage, a signal generation unit which receives the first voltage and the second voltage and generates a second signal, and a second switch which selects whether to supply the driving current to the second light source by the second signal.