Emergency LED Driver Terminal Reduction via Merged Switch and Indicator Circuit
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Solution Overview
Problem
Emergency converters for lighting applications require multiple signal lines and terminals for test switches, status indicator lights, and duration selection interfaces, leading to increased complexity, space requirements, and costs, despite existing solutions that attempt to consolidate these functions.
Innovation Solution
The emergency converter employs circuitry that allows detection of test switch and battery duration select switch actuations using a single input terminal, reducing the number of necessary terminals to three by utilizing a divider network and switching elements to manage the interfaces for a test switch, status indicator light, and duration selection, enabling a bicolour status indicator light to be driven with only two connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate terminals are used for test switch, status indicator light, and duration selection interface, then each component can be independently controlled and tested, but the number of terminals increases leading to higher complexity and costs
Solution Approach 1:
The patent combines the test switch and status indicator light into a single interface circuit that shares common terminals. The test switch is connected in parallel with the status indicator light, allowing both components to be controlled through the same terminal connections, thereby reducing the total number of terminals required while maintaining independent controllability through software logic in the microcontroller.
Solution Approach 2:
The shared interface terminals serve multiple functions: they can control the status indicator light to display operational states, detect test switch actuation, and provide a unified interface for both monitoring and testing operations. This multi-functional approach allows the same hardware terminals to perform different roles based on software configuration.
2Adaptability or versatility
If more terminals are used for interfaces, then more functions can be implemented, but the space requirements and costs increase
Solution Approach 1:
The interface circuit merges the test switch connection and status indicator light connection into a shared terminal structure. By connecting the test switch in parallel with the status indicator light, the patent reduces the number of required terminal connections while maintaining both testing and status indication functionalities through intelligent software control of the shared hardware resources.
3Adaptability or versatility
If the number of microcontroller pins is increased to accommodate all interfaces, then all functions can be implemented simultaneously, but the overall costs of the emergency converter increase
Solution Approach 1:
The patent implements a universal interface approach where a single microcontroller pin serves multiple purposes: it can drive the status indicator light through PWM control, detect test switch actuation through interrupt detection or voltage level sensing, and potentially support duration selection functions. This multi-functional pin usage reduces the total pin count required, allowing the use of lower-cost microcontrollers with fewer I/O pins while maintaining full functionality.
Solution Approach 2:
The interface architecture merges multiple control and detection functions into a shared pin connection. By combining the status indicator output and test switch input detection through the same terminal, the patent reduces the microcontroller pin requirements, thereby enabling the use of more cost-effective microcontroller units without sacrificing functional capability.
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 configuration effectively reduces the number of terminals required, allowing for a wide product portfolio with a single design, minimizing spatial and cost burdens while maintaining functionality, and enabling the use of pulse-width modulated outputs for diverse optical signals.
Implementation Method 1
a bicolour status indicator light, for example comprising a red light emitting diode (LED) and a green LED
Data Source
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AI summary
An emergency lighting converter used for providing a supply voltage to connected lighting modules for a predetermined time in case mains supply is failing comprises a test switch, a status indicator light with at least a first LED, a battery duration select switch and a control circuit, for example a microprocessor. The emergency converter comprises circuitry configured to enable the control circuit to detect if the test switch is actuated or the battery select switch is actuated using a single input terminal of the control circuit. According to an advantageous embodiment the status indicator light arranges a second LED in an antiparallel circuit topology to the first LED, and the circuitry is configured to drive the status indicator light from a first output terminal of the control circuit and a second output terminal of the control circuit.