Pyroelectronic Detonator Shunt Circuit for Transient Protection
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Solution Overview
Problem
Pyrotechnic headers with electronic circuits are sensitive to transient currents and electrostatic discharges, making them prone to unintended firing, and existing passive protection solutions are inadequate for ensuring safety and control.
Innovation Solution
A controllable, two-directional electrical shunt is implemented parallel to the electrothermal bridge, allowing for state selection between low resistance closed and high resistance open states, preventing or enabling firing based on command thresholds, and featuring monostable or bistable switching behaviors to manage electrical signals and currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive protection devices such as chopper circuits or limiters are implemented on the firing line interface, then safety against transient currents and electrostatic discharges is improved, but device complexity and loss of control flexibility increase
Solution Approach 1:
The patent introduces an intermediary element (the shunt circuit) placed in parallel with the electrothermal bridge. This shunt acts as a mediator that can selectively divert current away from the bridge during transient events, providing protection without requiring complex interface circuitry. The shunt circuit includes a switching element that can open or close to control current flow, offering a simpler alternative to passive protection devices while maintaining safety.
Solution Approach 2:
The patent employs a dynamic shunt circuit that can change its state based on control signals. The switching element can transition between open and closed states, allowing the system to adapt its protection level dynamically. This dynamic behavior enables the shunt to provide full current flow during normal operation and block current during transient events, offering flexible protection without the complexity of passive devices.
2Reliability
If the shunt is placed in closed state to prevent firing, then safety against unintended firing is improved, but loss of control flexibility and inability to fire the header increases
Solution Approach 1:
The shunt circuit is designed with a switching element that can dynamically change its state between open and closed based on control signals. When in the closed state, the shunt prevents current flow to the bridge, ensuring safety. When opened, it allows full current flow to the bridge, enabling firing. This dynamic controllability resolves the contradiction by allowing the system to switch between safety and firing capabilities as needed.
Solution Approach 2:
The system incorporates feedback mechanisms where the control unit monitors the state of the shunt and adjusts it accordingly based on operational requirements. The feedback loop ensures that the shunt remains closed during transient events to prevent unintended firing, while automatically opening when normal operation is required, thus maintaining both safety and control flexibility.
3Reliability
If monostable shunt is used with switchover threshold, then automatic protection against transient currents is improved, but response time and switching speed are reduced
Solution Approach 1:
The patent utilizes parameter changes in the shunt circuit's switching threshold to achieve automatic protection. The monostable shunt is configured with a specific switchover threshold that triggers automatic closing during transient currents. By adjusting this threshold parameter, the system can distinguish between normal operational currents and harmful transients, providing automatic protection while maintaining acceptable switching speeds through proper threshold selection.
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 active solution enhances safety by preventing unintended firing and allows for more comprehensive testing of headers under simulated conditions without actual discharge, offering improved control and reliability.
Implementation Method 1
It consists in sending in an electrothermal bridge in contact with a primary composition, via an electrical line, a current sufficient to cause the firing of the primary composition
Implementation Method 2
the shunt which is parallel to the bridge short-circuits substantially the bridge which then may not operate any longer and cause the firing
Data Source
AI summary
A pyroelectronic detonator (1) includes an electronic circuit for at least controlling the detonator ignition by supplying igniting current to an electrothermal bridge (4) and at least one electronic shunting element (7) directly connected to the bridge (4), wherein the shunting element (7) is controllable between the closed low-electric resistance state of the shunt and the open high electric resistance state thereof and the electronic circuit (2) controls the states. The shunt is constructed in such a way that it can be monostable and bistable.