Lighting Device Impedance Measurement for Accurate Light Source Identification
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Solution Overview
Problem
Conventional lighting devices face false operation due to voltage drops caused by contact resistance in connectors, leading to incorrect determination of light source units and improper power supply.
Innovation Solution
A lighting device with a controller that measures the impedance of a first impedance device connected to the light source unit without applying load current, allowing for accurate determination and control of power converter output to prevent false operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If voltage is applied across the light source circuit and identification circuit simultaneously through the connector, then the number of wirings is reduced, but voltage drop caused by contact resistance leads to false determination of light source unit type
Solution Approach 1:
The patent applies preliminary action by measuring the impedance of the identification circuit before applying voltage for lighting operation. The controller first measures impedance through the connector to determine the light source unit type, then subsequently applies voltage for normal operation. This sequential approach ensures accurate measurement is performed under optimal conditions (no voltage drop) before the system transitions to its operational state.
Solution Approach 2:
The patent segments the operation into two distinct phases: a measurement phase where only the identification circuit is activated through the connector for impedance measurement, and an operation phase where the light source circuit is activated for lighting. This segmentation allows the measurement function to be performed independently without interference from the lighting function, eliminating the voltage drop problem while maintaining wiring simplicity.
2Ease of operation
If connector is used for interconnection between power supply circuit and light source unit, then electrical connection is established, but contact resistance causes voltage drop leading to false operation
Solution Approach 1:
The patent performs the determination action preliminarily by measuring impedance through the connector before applying full operating voltage. The controller uses the measured impedance value to identify the light source unit type, ensuring accurate determination is completed before the system enters its operational mode where voltage drop would occur during normal lighting operation.
Solution Approach 2:
The patent changes the operating parameters during measurement by using only the identification circuit path through the connector, rather than applying full operating voltage to the entire light source circuit. This parameter change (measuring at low voltage/current through the identification circuit only) eliminates the voltage drop effect caused by connector contact resistance, ensuring reliable determination while maintaining ease of electrical connection.
3Extent of automation
If voltage is applied to determine light source unit type, then determination is performed, but voltage drop causes incorrect output and false operation
Solution Approach 1:
The patent implements preliminary action by performing impedance measurement through the identification circuit before applying voltage for lighting operation. The controller measures the impedance value, automatically determines the light source unit type based on this measurement, and then proceeds to apply appropriate voltage for operation. This ensures the automatic determination function operates with high precision by measuring under optimal conditions.
Solution Approach 2:
The patent uses the identification circuit as an intermediary element for measurement. Instead of measuring voltage or current directly in the light source circuit, the system measures impedance through the identification circuit connected in series with the connector. This intermediary measurement approach provides accurate data for automatic determination without being affected by voltage drop in the main power path.
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
The solution effectively prevents false determination and operation by isolating the impedance measurement from load current, ensuring accurate power supply to the light source unit and reducing voltage drops.
Implementation Method 1
The type determiner includes a dividing resistor to be connected in series with the identification circuit of the connected light source unit. The type determiner is configured to measure a resistance of the identification circuit (resistor) based on measurement of the voltage across the dividing resistor
Data Source
AI summary
The lighting device according to the present invention is used for lighting a light source device. The light source device includes a light source unit connected between first and second power supply terminals and a first impedance device which has an impedance associated with an electric property of the light source unit and is connected to the second power supply terminal. The lighting device performs a first process and a second process. In the first process, the lighting device obtains a measurement indicative of the impedance by supplying power to the first impedance device via the second power supply terminal while prohibiting output of DC power for lighting, and determine an operating condition based on the measurement. In the second process, the lighting device operates so that the DC power for lighting satisfies the operating condition.