Switch Contact Detection Circuit Using Capacitor Current Pulses
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Solution Overview
Problem
The formation of insulative films on silver contact points in switch status detection devices due to sulfurization leads to contact failure, and increasing current flow to prevent this results in higher power consumption.
Innovation Solution
A switch status detection device incorporating a power source, a first resistor, a first switch, a control device, and a first capacitor, where the capacitor is connected to the contact point and the power source, allowing a large momentary current to flow and then reducing power consumption by switching to a resistor-based path after charging, preventing insulative film formation without increased power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current flow through the switch is increased to prevent insulative film formation, then contact reliability is improved, but power consumption increases
Solution Approach 1:
The patent applies periodic action by using a capacitor to generate momentary current pulses during switch operation. The capacitor charges and discharges periodically, creating high current flow only during the brief switching instant when it is most needed to prevent insulative film formation, rather than maintaining continuous high current flow that would waste power.
Solution Approach 2:
The patent applies preliminary action by pre-charging the capacitor before the switch operation. The capacitor is charged in advance through a charging circuit, so that when the switch needs to operate, the capacitor is already ready to deliver the high momentary current needed to prevent insulative film formation, eliminating the need for continuous power consumption.
2Duration of action of stationary object
If momentary current is increased to prevent insulative film formation, then switch lifespan is extended, but energy consumption increases
Solution Approach 1:
The capacitor-based circuit generates high current flow only during brief periodic moments when the switch operates, rather than maintaining continuous high current. This periodic high current delivery extends switch lifespan by preventing insulative film formation while minimizing energy loss because the high current exists only for short durations during switching events.
Solution Approach 2:
The patent changes the temporal parameter of current flow from continuous to pulsed/momentary. By using the capacitor to deliver current in short high-intensity pulses during switching events rather than continuous flow, the system achieves the same protective effect on the switch contact points while significantly reducing overall energy consumption.
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 insulative film formation on contact points while maintaining low power consumption by ensuring a high momentary current flow initially and then reducing it to below 1 mA, thereby extending switch lifespan without increasing energy usage.
Implementation Method 1
The first capacitor has one end connected to the first contact point at a position on the first current path on a side of the first resistor with respect to the first contact point, and the other end connected to the power source or the ground
Data Source
AI summary
A switch status detection device includes a power source, a first resistor, a first switch, a control device, and a first capacitor. The first resistor has one end connected to the power source. The first switch is configured to switch between a connected state and a disconnected state of a first contact point, provided on a first current path between the other end of the first resistor and ground. The control device detects an on/off status of the first switch, on a basis of a voltage at the other end of the first resistor. The first capacitor has one end connected to the first contact point at a position on the first current path on a side of the first resistor with respect to the first contact point, and the other end connected to the power source or the ground.