Contact Input Impedance Switching for Faster State Change Recognition
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Solution Overview
Problem
Conventional methods for recognizing valid state changes in capacitively coupled signals in electronic circuitries face challenges due to parasitic capacitive coupling, leading to delayed recognition and increased power dissipation, limiting the number of contact inputs and response time.
Innovation Solution
The method involves actively controlling the impedance of contact inputs by dynamically adjusting resistance during state transitions, increasing current draw only during transitions and OFF states to reduce power consumption and improve response time, using a signal converter, switch, current generator, impedance controller, and input state logic circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the debounce timer duration is increased to reject capacitively coupled pulses, then false input state changes are reduced, but the recognition time for valid contact input transitions is delayed
Solution Approach 1:
The patent applies dynamic impedance adjustment by switching between a first impedance value (during validation) and a second impedance value (during steady state). The impedance controller dynamically changes the contact input impedance based on the validation state, allowing the system to optimize both response time and false signal rejection by adapting the impedance to the current operational phase rather than using a fixed impedance value
Solution Approach 2:
The patent changes the electrical parameter (impedance) of the contact input circuitry from a static value to a dynamic value that varies with operational state. By transitioning between two distinct impedance values based on whether validation is occurring or steady state is maintained, the system resolves the contradiction between response time and reliability
2Productivity
If the impedance of the contact input is reduced to mitigate capacitively coupled transients, then the debounce timer setting can be smaller, but the power dissipation by the contact input circuitry increases
Solution Approach 1:
The patent implements periodic action by alternating between two impedance states: a lower impedance value during validation periods (when fast response is needed) and a higher impedance value during steady state periods (when power conservation is prioritized). This periodic switching between impedance levels allows the system to achieve fast response when necessary while minimizing power dissipation during normal operation
Solution Approach 2:
The dynamic adjustment of impedance based on operational state allows the system to optimize the balance between response speed and power consumption. The impedance controller switches between impedance values only when needed for validation, rather than maintaining a continuously low impedance that would cause excessive power dissipation
3Quantity of substance
If the number of contact inputs is increased in a device, then more communication channels are available, but the power dissipation and heat generation limit the maximum number of inputs
Solution Approach 1:
By making the impedance dynamic rather than static, the patent enables contact input circuitry to consume less power during steady state operation. This allows more contact inputs to be packed into a device without exceeding power dissipation limits, as each input consumes power only during brief validation transitions rather than continuously
Solution Approach 2:
The periodic switching between high and low impedance states means that power is consumed only during brief validation intervals rather than continuously. This periodic power consumption pattern allows a higher density of contact inputs to be implemented, as the average power dissipation per input is significantly reduced
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 approach reduces power consumption during steady-state operation, enhances recognition time, and increases the number of contact inputs without overheating, providing improved immunity to capacitively coupled signals.
Implementation Method 1
a capacitively coupled signal will also discharge via a parasitic capacitance (Cline, as shown in FIG. 2) through the contact input Rb
Implementation Method 2
the long bundle of cables typically used to connect these devices is known to introduce large parasitic capacitive coupling between individual conductors carrying the monitored signals
Data Source
AI summary
A method for recognizing a valid change of state in a communication signal including capacitively coupled signals received by an input contact includes maintaining the input contact in a first state and an impedance of the first contact input in a first impedance level, validating that the communication signal sent from to the input contact is a valid change of state, and changing the input contact to a second state and the impedance of the first input contact input to a second impedance level when the voltage signal is validated. An input contact circuit is also disclosed.