Vehicle Headlamp Circuit Layout for Low-Beam Fail-Safe Control
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Solution Overview
Problem
Existing vehicle headlamp light assemblies face safety issues due to the inability to deactivate the high beam function without also deactivating the low beam function when a switch fails, posing risks in fail-safe modes.
Innovation Solution
A light assembly design with the high beam function placed in a high side position, using series switching units and protection diodes to maintain the low beam function's activation even in case of switching unit failures, and allowing for additional lighting functions like daytime running light or position lighting without parallel switches, utilizing a single driver for multiple functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a switch is mounted in parallel to the high beam module to control the high beam function, then the high beam can be turned on and off independently, but when the switch fails in open-circuit position, the high beam cannot be deactivated without also deactivating the low beam function
Solution Approach 1:
The patent removes the parallel switch component from the circuit configuration. Instead of using a switch in parallel to the high beam module, the invention uses a series switching unit that controls power delivery to the high beam module through the driver circuitry, eliminating the component that causes the fail-safe issue while maintaining independent control capability
Solution Approach 2:
The patent inverts the switching configuration from a parallel switch arrangement to a series switching unit arrangement. The series switching unit is positioned between the driver and the high beam module, changing the topological structure from parallel to series connection, which fundamentally alters the failure mode behavior
2Device complexity
If multiple lighting functions are performed by a single light assembly, then device complexity is reduced, but control reliability of individual functions deteriorates when a switch fails
Solution Approach 1:
The driver circuit is designed to provide multiple power outputs that can serve different lighting functions (high beam, low beam, daytime running lights) through a single multi-functional driver unit, reducing the need for separate control circuits while maintaining reliable independent control of each function through series switching units
Solution Approach 2:
The patent segments the control function by introducing individual series switching units for each lighting module (high beam module, low beam module) within the multi-functional assembly. This allows each function to be controlled independently through its own switching unit while sharing the common driver infrastructure
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures the low beam function remains active in failure scenarios, enhances safety, and allows flexible control of multiple lighting functions with improved reliability and cost-effectiveness by using LEDs and protection diodes, while maintaining functionality with a single power source.
Implementation Method 1
the first lighting module may comprise a first protection diode in parallel to the first series of LEDs and mounted in reverse, and/or the second lighting module may comprise a second protection diode in parallel to the second series of LEDs and mounted in reverse
Implementation Method 2
the light assembly may further comprise a third protection diode between the first switching unit and the first lighting module
Data Source
AI summary
A light assembly includes a power source, a first lighting module to perform a high beam function, a second lighting module to perform a low beam function and a driver connected to the voltage source. The driver is connected to a first pin, a second pin and a third pin and is configured to apply a first power output to a first lighting module and to apply a second power output to the second lighting module. The light assembly includes a first switching unit in series with the first lighting module and the second lighting module, and a second switching unit in series with the second lighting module.