Bus Interface Lockout Prevention via Voltage Monitoring
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Solution Overview
Problem
In decentralized bus power supply systems, such as those used in DALI bus interfaces, a lockout state can occur when the last active local power supply module is inadvertently switched off, leading to a loss of power and communication disruption.
Innovation Solution
A bus interface with a control circuitry that monitors the bus voltage level after switching off the internal power supply and reactivates it or sends a message when the voltage drops below a threshold, preventing lockout situations by ensuring continuous power supply when no other active power sources are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the internal power supply is switched off to save energy or respond to control commands, then power consumption is reduced, but a lockout situation occurs when the last active power supply is switched off, causing bus voltage loss and communication disruption
Solution Approach 1:
The control circuitry continuously monitors the bus voltage level and uses this feedback to determine whether to maintain the switched-off state or reactivate the internal power supply. When the bus voltage drops below a threshold after switching off, the system detects this condition and reactives the power supply to prevent lockout, thus resolving the contradiction between energy saving and power supply reliability.
Solution Approach 2:
Before completely switching off the internal power supply, the control circuitry performs a preliminary check by monitoring the bus voltage level after switching off. This preliminary action allows the system to detect whether other power supplies are still active on the bus, preventing the lockout condition from occurring in the first place.
2Reliability
If decentralized local power supply modules are used instead of central bus power supply, then system reliability and modularity are improved, but the risk of lockout situations increases when the last active module is switched off
Solution Approach 1:
Each decentralized power supply module autonomously monitors the bus voltage level and independently decides whether to reactivate its own internal power supply based on detected voltage conditions. This self-service capability eliminates the need for complex centralized control logic while maintaining system reliability, as each module can detect and respond to lockout conditions independently.
3Ease of operation
If the internal power supply is switched off based on control commands, then system control flexibility is improved, but communication disruption occurs when the last active power supply is switched off
Solution Approach 1:
The control circuitry ensures continuous monitoring of the bus voltage level even after switching off the internal power supply based on control commands. This continuous action allows the system to detect when the bus voltage drops to critical levels and reactivate the power supply in time, preventing communication disruption and maintaining continuous useful action on the bus.
Data Source
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AI summary
The present invention relates to a module for providing a powered interface, comprising at least one terminal configured to connect a bus having a non-zero DC voltage level in the quiet state; an internal power supply configured to supply a connected bus with DC power, wherein the internal power supply is designed such that it can be switched off; and a control circuitry configured to control the internal power supply, and communicate by receiving and/or sending signals over the bus. The control circuitry of the driver circuit is further configured to carry out the following steps upon receipt of an internal power supply switch-off command: switching off the internal power supply and detecting the bus voltage level at a predetermined time after switching off the internal power supply; and continuing the switched-off state of the internal power supply, when it is determined that the detected bus voltage level is above a threshold value; and switching on again the internal power supply and/or sending out a message over the bus, when it is determined that the detected bus voltage level at the predetermined time after switching off drops to or below the threshold value.