KNX Bus Output Protection Circuit for Short-Circuit Overheating
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Solution Overview
Problem
Existing KNX bus management devices lack effective protection against excessive overheating due to permanent short-circuit failures in the emission resistance, which can lead to fire hazards and safety issues.
Innovation Solution
An electronic KNX bus management device with an integrated protection circuit that monitors the emission output for permanent short-circuit states and instantly interrupts the current flow through the emission resistance, preventing overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transmission resistor is used in normal pulsed operation, then the average power dissipated is very low and the resistor can be sized for 1-2W, but in the event of a permanent short-circuit failure, the power dissipated can reach 13-33W causing excessive overheating and fire hazards
Solution Approach 1:
The protection circuit performs preliminary monitoring of the transmission output state before excessive power dissipation occurs. By continuously detecting whether the transmission output is in a transient or permanent short-circuit state, the circuit can preemptively activate the protection transistor to interrupt current flow, preventing the temperature rise that would lead to safety hazards.
Solution Approach 2:
The protection circuit implements feedback by monitoring the transmission output state and using this information to control the protection transistor. The circuit compares the detected state against safety thresholds and adjusts the circuit operation accordingly, activating protection when a permanent short-circuit is detected and normal operation when transient short-circuits occur during data transmission.
2Reliability
If a protection circuit is added to detect permanent short-circuits, then safety is improved by preventing excessive overheating, but the device complexity increases
Solution Approach 1:
The protection transistor acts as an intermediary element between the transmission circuit and the power supply. This single component, controlled by the protection circuit, serves as the mediator that can quickly interrupt current flow to protect the transmission resistor, providing safety functionality without requiring complex protection mechanisms.
Solution Approach 2:
The protection circuit uses the existing transmission output state information to automatically determine when protection is needed, without requiring external monitoring or complex control systems. The circuit self-regulates by comparing the transmission output state against predefined conditions and autonomously activating the protection transistor when necessary.
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 excessive overheating and potential fires by immediately detecting and responding to permanent short-circuits, enhancing the safety and reliability of KNX bus management systems.
Implementation Method 1
the average power dissipated in the transmit resistor is very low since it only conducts current during each pulse and the duration of each pulse is short
Implementation Method 2
a protection transistor, called a T1 transistor, in an N-channel enhancement insulated gate field effect transistor (MOSFET) family
Data Source
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AI summary
The present invention relates to an electronic device for managing a KNX or similar bus, with electronic component protection, comprising a main pulsed current electronic circuit (1) capable of managing data transmission in such a bus and comprising an electronic data transmission circuit (1a) having an output (10a) delivering a pulsed signal for transmitting said data and being transiently, at each pulse, short-circuited to ground, a connection point (1b) to said bus and a resistor (R1).It further includes an electronic protection circuit (3, 4) configured and connected to said main electronic circuit so as to monitor the state of said output to detect a permanent short-circuit state of the latter following a possible failure of said electronic emission circuit and to instantly trigger an opening of said main electronic circuit which has the effect of instantly interrupting the flow of electric current in said resistor.