Short-Circuit Protection Circuit With Thyristor-Latched Switch Cutoff
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing short-circuit protection circuits in power supply systems suffer from low reliability due to incomplete turn-off of the switch transistor, leading to potential damage to the load or power supply system.
Innovation Solution
A short-circuit protection circuit incorporating a comparison circuit, current sampling circuit, control circuit with a thyristor and switch transistor, and a voltage stabilizing circuit to ensure complete disconnection of the power supply from the load by keeping the thyristor in an on-state until an off signal is received.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a switch transistor is used for fast response in short-circuit protection, then the response speed is improved, but the switch transistor may fail to turn off completely leading to low reliability
Solution Approach 1:
A thyristor is introduced as an intermediary component between the control signal and the switch transistor. The thyristor acts as a mediator that maintains the switch transistor in a fully off state during short-circuit conditions, ensuring complete disconnection even though the switch transistor responds instantly. This resolves the contradiction by using the thyristor's latching特性 to guarantee reliable cutoff while preserving the fast response capability of the switch transistor.
2Reliability
If the drive time of the switch transistor is extended to ensure complete turn-off, then the reliability is improved, but the response time increases and protection becomes slower
Solution Approach 1:
The control circuit is designed to activate the thyristor in advance when a short-circuit condition is detected. The thyristor is triggered to turn on the switch transistor completely off before the short-circuit current can cause damage. This preliminary action ensures that the switch transistor remains fully off throughout the short-circuit event, achieving both fast response and complete disconnection reliability without requiring extended drive time.
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
Ensures reliable short-circuit protection by ensuring the switch transistor is completely turned off, enhancing the validity and reliability of the protection mechanism.
Implementation Method 1
the thyristor of the control circuit will be kept in an on-state to ensure that the switch transistor is completely turned off
Data Source
AI summary
The invention provides a short-circuit protection circuit and a lighting device. A control circuit comprises a thyristor and a switch transistor. A comparison circuit is electrically connected to a power supply, one terminal of a current sampling circuit and one terminal of the thyristor, the other terminal of the current sampling circuit is electrically connected to a first terminal of the switch transistor, a second terminal of the switch transistor is electrically connected to a second terminal of the thyristor, a third terminal of the switch transistor is electrically connected to an external load. By adopting the invention, the thyristor can be kept in an on-state to control on-off of the switch transistor so as to ensure that the switch transistor can be completely turned off, thus effectively improving the validity and reliability of short-circuit protection.