Logic Circuit Power Supply Interruption via MOSFET Switch
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Solution Overview
Problem
Existing electrical circuit arrangements for protecting logic circuit devices do not adequately ensure the safety of these devices in the event of malfunctions, as they lack a robust mechanism to prevent further errors or errors accumulation after a malfunction is detected.
Innovation Solution
Incorporating a controllable switch in the supply path of the circuit arrangement, where the error detection unit, implemented within the logic circuit device, controls the switch to interrupt the supply path upon detecting a malfunction, thereby disconnecting the logic circuit device from the voltage supply, and using a power MOSFET as the switch to minimize heat losses, along with signal isolation via an optocoupler in the control line to ensure galvanic isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a controllable switch is added to interrupt the supply path upon error detection, then the safety and reliability of the logic circuit device is improved, but the device complexity increases
Solution Approach 1:
The circuit arrangement is segmented into distinct functional blocks: the logic circuit device, the error detection unit, the controllable switch, and the drive circuit. This segmentation allows each component to perform its specific function independently, improving reliability through modular error isolation while managing complexity by organizing functions into separate units.
Solution Approach 2:
The error detection unit continuously monitors the logic circuit device before failures can propagate. The controllable switch is pre-positioned in the supply path, ready to interrupt power immediately upon error detection. This preliminary preparation ensures rapid response to malfunctions, enhancing safety without requiring complex real-time decision-making circuits.
2Reliability
If the supply path is interrupted to prevent error accumulation, then the reliability is improved, but the productivity and operational continuity deteriorate
Solution Approach 1:
The error detection unit provides continuous feedback about the operational status of the logic circuit device. When an error is detected, this feedback triggers the controllable switch to interrupt the supply path. This closed-loop feedback mechanism ensures that power is cut only when necessary, preventing error accumulation while minimizing disruption to operational continuity during normal operation.
Solution Approach 2:
The system performs self-diagnosis through the error detection unit, which automatically monitors the logic circuit device and triggers the protective action without external intervention. This self-service capability allows the system to maintain high productivity during normal operation while automatically ensuring reliability when errors occur, without requiring constant external monitoring.
3Loss of energy
If a power MOSFET is used as the controllable switch, then the heat losses are reduced, but the manufacturing complexity increases
Solution Approach 1:
The controllable switch is designed as a power MOSFET, which changes the electrical parameters of the supply path by providing very low on-resistance during the conducting state. This parameter optimization significantly reduces heat losses (P = I²R) at the switch. While MOSFETs are more complex than simple mechanical switches, their integration-friendly nature and well-established manufacturing processes make them practical for modern electronic circuit production.
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 solution effectively prevents subsequent errors or error accumulation by disconnecting the logic circuit device from the voltage supply upon detection of a malfunction, enhancing the safety of the logic circuit device and the overall circuit arrangement by isolating it from power, and allows for controlled reconnection when necessary.
Implementation Method 1
an isolating distance is arranged in the control line or in at least one of the control lines. The isolating distance ensures galvanic isolation of the error detection unit and the switch. Isolating distances are preferably provided in all control lines or one isolating distance is provided for all control lines. The isolating distance is implemented in particular by means of an optocoupler.
Implementation Method 2
The controllable switch is preferably in the form of a power transistor, particularly preferably in the form of a power MOSFET (MOSFET: metal-oxide-semiconductor field-effect transistor). In particular, the power transistor has a low contact resistance when switched on. This reduces the heat losses at the transistor.
Data Source
Figure 1
Figure 2
AI summary
The electric circuit arrangement (10) has a supply path (16) for electrical connection of a logic circuit unit (12) with a voltage supply unit (18), and an error detection unit for detecting the malfunction of the circuit arrangement, particularly the malfunction of the logic circuit unit. A controllable switch (20) is arranged in the supply path for interrupting the supply path. The error detection unit is implemented in the logic circuit unit and is connected with the switch for controlling the interruption of the supply path through the switch in response to malfunction over a control path.