Drive Circuit for Object Switches with Redundant Off Control
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Solution Overview
Problem
Conventional drive circuits for parallel-connected object switches may malfunction due to faults in the off control unit, leading to unintended switching states, particularly when off holding switches fail to maintain the OFF state.
Innovation Solution
The drive circuit incorporates off holding switches driven by both an own control unit and at least one other control unit, ensuring that even if a fault occurs in the primary control unit, the off holding switches can be maintained in the correct state by an alternate control unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single off control unit is used to drive each off holding switch, then the device complexity is reduced, but the reliability deteriorates because a fault in the control unit causes malfunction of the off holding switch
Solution Approach 1:
The patent assigns different functional roles to different control units: the first off control unit primarily controls the first off holding switch, while the second off control unit serves as a backup that can take over control of the first off holding switch if the first control unit fails. This differentiation of control functions between units resolves the contradiction by providing specialized redundancy without requiring complete duplication of the control system.
Solution Approach 2:
The patent implements a backup control mechanism where the second off control unit is prepared in advance to take over control of the first off holding switch if the first off control unit fails. This beforehand cushioning ensures that potential failures are mitigated before they cause actual malfunctions, resolving the reliability concern while maintaining a relatively simple overall system structure.
2Reliability
If multiple control units are used to drive each off holding switch, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The second off control unit is designed with multi-functionality: it normally controls the second off holding switch but can also take over control of the first off holding switch if needed. This universal design allows a single control unit to perform multiple functions, providing redundancy and improved reliability without requiring additional dedicated backup control units, thus limiting the increase in device complexity.
3Reliability
If off holding switches are provided for each object switch, then the reliability of object switch control is improved, but the device complexity and quantity of components increases
Solution Approach 1:
The patent combines control functions by allowing the second off control unit to control both the second off holding switch and the first off holding switch (as a backup). This merging of control responsibilities reduces the need for completely independent control paths for each off holding switch, thereby reducing overall device complexity while maintaining the reliability benefit of having dedicated off holding switches for each object switch.
Data Source
AI summary
A drive circuit is provided for driving a plurality of object switches mutually connected in parallel. The drive circuit includes: an off holding switch provided for each of the object switches, short-circuiting between a control terminal of each object switch and a reference potential unit to which discharge from the control terminal is discharged; and off control units each provided for the off holding switch. The off holding switch is driven by an own control unit and other control units. The own control unit is provided as an off control unit corresponding to own off holding switch, among the off control units. Other control units are at least one of the off control units other than the own control unit.