Self-Powered Detection Device with Non-Volatile Memory and Clamp Circuit
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Solution Overview
Problem
Existing self-powered detection devices for tamper events require continuous power sources, leading to limited functionality and security risks due to battery life and potential disruption by perpetrators, and existing solutions are either expensive or complex and not well-suited for integration with small volume devices.
Innovation Solution
A self-powered detection device with a non-volatile memory unit and sensor that uses a clamp circuit to harness energy from physical or chemical events, allowing for secure storage and reading of tamper events without continuous power, featuring a diode clamp to prevent unauthorized resets and protect the memory cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a continuous power source (battery) is used to power the detection device, then the sensor can continuously detect and the electronic circuit remains functional, but the device has limited lifetime due to battery depletion and security risks from potential power disruption by perpetrators
Solution Approach 1:
The detection device harvests energy from the detected physical event itself (mechanical stress, vibration, or other external stimuli) to power the sensor and electronic circuit temporarily. The sensor detects an event, converts the mechanical energy from that event into electrical energy, and uses this harvested energy to power the detection and recording functions without requiring a continuous external power source or battery replacement
Solution Approach 2:
The patent replaces the traditional mechanical battery-powered system with an energy harvesting system that converts physical events (mechanical stress, vibration) directly into electrical energy. This substitution eliminates the need for chemical batteries and their associated limitations of finite capacity and replacement requirements
2Duration of action of moving object
If a self-powered detection device without continuous power is used, then device lifetime is extended and security risks are reduced, but the device cannot function when power is not supplied and requires complex energy harvesting mechanisms
Solution Approach 1:
The patent combines the sensor element with the energy harvesting function into a single integrated system. The same physical structure that detects the event also harvests energy from that event, eliminating the need for separate power generation components and reducing overall device complexity
Solution Approach 2:
The sensor element serves multiple functions: it acts as both the detection mechanism for physical events and the energy harvesting device that converts those events into electrical power. This multi-functionality reduces the number of components needed and simplifies the overall system architecture
3Productivity
If a memory writing circuit is always connected to the sensor, then the device can immediately record detected events, but unauthorized resetting of the memory becomes possible and power consumption increases
Solution Approach 1:
The patent implements a clamp circuit that is pre-configured to block unauthorized reset signals before they can reach the memory cell. The clamp circuit is designed with a specific threshold voltage that allows legitimate write operations from the sensor while blocking any attempt to reset the memory by applying a voltage of opposite polarity, thus preventing unauthorized resetting in advance
Solution Approach 2:
The clamp circuit acts as an intermediary protective element positioned between the sensor/memory write circuit and the memory cell. This intermediary component selectively allows legitimate write operations while blocking harmful reset attempts, thus mediating between the detection system and the memory storage without requiring continuous power
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
Enables efficient and secure detection and recording of tamper events using minimal electrical energy, preventing unauthorized resets and ensuring device functionality without continuous power, while being cost-effective and adaptable for integration in small volume devices.
Implementation Method 1
a sensor which is activated by a physical or chemical action or phenomenon applied on it... the sensor forming an energy harvester that transforms energy from said physical or chemical action or phenomenon into an electrical stimulus pulse
Data Source
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AI summary
The self-powered detection device comprises a Non-Volatile Memory (NVM) unit (52) formed at least by a NVM cell and a sensor which is activated by a physical or chemical action or phenomenon, this sensor forming an energy harvester that transforms energy from said physical or chemical action or phenomenon into an electrical stimulus pulse, said NVM unit being arranged for storing in said NVM cell, by using the electrical power of said electrical stimulus pulse, a bit of information relative to the detection by said sensor, during a detection mode of the self-powered detection device, of at least one physical or chemical action or phenomenon applied to it with at least a given strength or intensity and resulting in a voltage stimulus signal provided between a set control terminal (SET) and a base terminal (SET *) of said NVM unit with at least a given set voltage. The self-powered detection device comprises a read circuit (56) or is arranged to be coupled to such a read circuit and further comprises a clamp circuit (54) located between the sensor and the NVM unit, this clamp circuit being arranged for passing said voltage stimulus signal on a set line connecting the sensor and the set control terminal of the NVM unit, this voltage stimulus pulse having a polarity corresponding to a set polarity of said NVM cell, and for blocking other voltage signals having approximately an amplitude corresponding to said set voltage or higher and an inverse polarity relative to the set polarity of said NVM cell, in order to avoid a possible erase of this NVM cell by such other voltage signals.