Transient Current Surge Limiter for LED Load Fluctuations
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Solution Overview
Problem
Existing light devices for motor vehicles using semiconductor light sources, such as LEDs, face the challenge of large transient current peaks when switching between lighting modes, which can damage the light sources due to abrupt changes in load, and previous solutions like energy absorption in resistors result in energy loss.
Innovation Solution
A device with control means that selectively switches the power supply between groups of light sources, using a power supply circuit and interruption means to manage the activation state and prevent transient current peaks by deactivating the power supply circuit and short-circuiting one group before reactivating it, thereby avoiding energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a switch is used to short-circuit one group of LEDs to change lighting modes, then lighting mode switching is achieved, but large transient current peaks occur that can damage the LEDs
Solution Approach 1:
The patent applies preliminary action by deactivating the power supply circuit before switching the interrupting means to short-circuit the LED group. This sequence prevents transient current peaks from occurring during mode switching, as the power supply is already off when the load configuration changes. The control means coordinates these actions to ensure the power supply circuit is deactivated first, then the interrupting means switches, eliminating the harmful current surge that would otherwise damage the LEDs.
2Reliability
If a resistor is used to absorb transient peaks, then LED protection is achieved, but energy is lost in the resistor
Solution Approach 1:
The patent extracts the energy absorption function from the resistor and transfers it to the power supply circuit itself. By deactivating the power supply circuit before switching occurs, the system naturally absorbs any transient energy through the controlled shutdown process rather than requiring a separate resistor to dissipate it. This eliminates the continuous energy loss that would occur with a resistor-based solution while maintaining LED protection.
3Reliability
If resistor-based peak absorption is implemented, then transient peaks are reduced, but device complexity increases and resizing is needed for each assembly
Solution Approach 1:
The patent makes the power supply circuit multi-functional by giving it both the primary function of powering the LEDs and the secondary function of absorbing transient peaks during switching. This universal approach eliminates the need for separate resistor components and their associated sizing calculations for different LED assemblies. The same power supply circuit design can be used across various configurations without requiring component resizing, reducing device complexity while maintaining transient peak reduction.
Data Source
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AI summary
The invention presents a device and a method for controlling the power supply to a plurality of light sources, comprising a first group including at least one light source, connected in series with at least a second group including at least one light source. The device includes a power supply circuit to which the plurality of light sources is connected as a load. According to the measures of the invention, it becomes possible to short-circuit at least one of the groups of light sources without generating high-intensity transient current spikes in the non-short-circuited light sources.