LED Control Device Diode Identification via Contact Pair
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lighting control devices for motor vehicles with light emitting diodes (LEDs) face challenges in adapting to new LED units due to corrosion issues at electrical contacts, requiring additional contacts for digital parameter transmission, which can lead to data transmission disturbances during unit exchange.
Innovation Solution
A method where a control device uses a contact pair to generate a measurement current when the LED is off, identifying the diode type based on voltage measurements between contacts, allowing parameter setting without additional digital contacts, and using existing electronic components to prevent corrosion and ensure reliable diode type recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional electrical connection contacts are provided for digital parameter transmission, then parameter values can be reliably transmitted, but corrosion occurs at contacts during operation leading to data transmission disturbances
Solution Approach 1:
The patent combines the power transmission contacts and parameter identification functions into a single contact pair. The control device identifies diode type by measuring electrical characteristics (forward voltage, current-voltage curves) through the existing power contacts during brief measurement cycles, eliminating the need for separate digital communication contacts and thereby avoiding corrosion-related data transmission issues.
Solution Approach 2:
The contact pair serves multiple functions: it transmits operating current to the LED arrangement and simultaneously identifies the diode type through electrical characteristic measurements. This multi-functionality reduces the number of contacts required and eliminates the corrosion problem associated with additional dedicated parameter transmission contacts.
2Device complexity
If measurement current is generated through existing contact pair, then additional contacts are avoided, but corrosion prevention must be ensured during operation
Solution Approach 1:
The control device performs periodic measurement cycles at brief intervals (e.g., during startup or in idle periods) to identify diode type through the contact pair. These measurements are conducted when the LED is not emitting light, using low measurement currents that do not cause overheating or accelerate corrosion, while still maintaining reliable parameter detection.
Solution Approach 2:
The diode type identification is performed in advance before normal operation begins, during startup sequences or idle periods. This preliminary measurement ensures the correct operating parameters are established without requiring continuous measurement currents during operation, thereby preventing contact corrosion while maintaining system reliability.
3Illumination intensity
If operating current parameters are adapted to diode type, then minimum brightness requirements are met, but diode type must be identified first
Solution Approach 1:
The control device uses feedback from electrical characteristic measurements (forward voltage, current-voltage curves) taken through the contact pair to automatically identify the diode type. Based on this feedback, the control device automatically selects and applies the appropriate operating current parameters to ensure the LED arrangement achieves the required minimum brightness without manual intervention.
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
This approach prevents corrosion and ensures reliable diode type identification and parameter setting without additional contacts, maintaining data integrity and facilitating seamless LED unit exchanges, enhancing operational safety and reducing maintenance complexity.
Implementation Method 1
The control device, with the lighting unit switched off, that is to say when the light emitting diode arrangement thereof is inactive or dark or non-luminous, to generate a measurement current which flows through the lighting unit via the contact pair. The control device thereupon identifies a measurement value of a predetermined measurement variable, for example of an electrical voltage which arises or is dropped between the contacts of the contact pair, said measurement value resulting on account of the measurement current.
Data Source
AI summary
A control device drives an operating current of a lighting unit formed with light emitting diodes. The lighting unit is connected to a contact pair of the control device. The control device sets at least one parameter of the operating current that depends on a diode type of the lighting unit. With the lighting unit switched off, the control device generates a measurement current and ascertains a measurement value to identify the diode type. A hysteretic regulator sets the parameter of the operating current, and a current source circuit sets a reference signal at a comparator during the operation of the lighting unit. With the lighting unit inactive, the current source circuit generates the measurement current. Alternatively, a precharge device of the control device charges an output capacitance at the contact pair by a predetermined precharge routine, and a deviation from a predetermined expected value is ascertained as the measurement value.