Adaptive Current Limiter Voltage Inversion Control
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Solution Overview
Problem
Current current limiters in telecommunications power systems face challenges in dynamically adjusting their behavior to accommodate varying input voltages, leading to either premature circuit breakage at lower voltages or potential damage at higher voltages due to fixed current limit settings.
Innovation Solution
An adaptive current limiter is introduced, comprising a circuit breaker, a sensing resistor, and a variable reference voltage generator that provides a voltage inversely proportional to the input voltage, allowing for a dynamic current limit set point that adjusts with input voltage changes, ensuring constant power delivery while preventing overloads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed current limit setting is used in current limiters, then the circuit breaker provides stable protection at a predetermined current threshold, but it causes premature circuit breakage at lower input voltages or potential damage at higher input voltages due to inability to adapt to varying voltage conditions
Solution Approach 1:
The patent applies the Dynamics principle by transitioning from a fixed current limit setting to a dynamic current limit that varies with input voltage. The circuit breaker continuously adjusts its trip threshold based on real-time voltage measurements, enabling it to adapt to changing operating conditions. This resolves the contradiction by making the protection mechanism both reliable (through consistent power-based limiting) and adaptable (through voltage-dependent threshold adjustment).
Solution Approach 2:
The patent implements Parameter changes by modifying the current limit parameter based on input voltage levels. Instead of maintaining a constant current threshold, the system changes the threshold parameter dynamically according to the measured voltage, ensuring that the product of current and voltage (power) remains within safe limits across varying voltage conditions. This directly addresses the adaptability issue while maintaining protection reliability.
2Object-affected harmful factors
If the current limit is set to prevent damage at higher voltages, then protection is improved at high voltage conditions, but premature circuit breakage occurs at lower voltages due to overly restrictive current threshold
Solution Approach 1:
The system dynamically changes the current threshold parameter based on input voltage levels. At higher voltages, the current threshold is reduced to prevent overpower conditions, while at lower voltages, the threshold is increased to allow normal operation. This parameter adaptation resolves the contradiction by providing appropriate protection levels without causing unnecessary circuit interruptions.
Solution Approach 2:
The circuit breaker incorporates feedback by continuously monitoring the input voltage and adjusting the current limit accordingly. This closed-loop control ensures that the circuit responds appropriately to voltage variations, maintaining both protection and availability. The feedback mechanism allows the system to learn from operating conditions and adjust its behavior in real-time.
3Productivity
If the current limit is set to allow normal operation at lower voltages, then circuit availability is improved, but the circuit may be damaged at higher voltages due to insufficient current restriction
Solution Approach 1:
The system dynamically adjusts the current limit based on real-time voltage measurements, allowing higher current thresholds at lower voltages for normal operation while automatically reducing the threshold at higher voltages to prevent damage. This dynamic adaptation resolves the contradiction by making the protection level contingent on operating conditions rather than fixed.
4Adaptability or versatility
If a variable reference voltage generator providing voltage inversely proportional to input voltage is implemented, then adaptability to varying input voltages is improved, but device complexity increases due to additional circuit components
Solution Approach 1:
The patent introduces a variable reference voltage generator as an intermediary component that simplifies the overall control logic. By generating a reference voltage that is inversely proportional to the input voltage, this intermediary element enables straightforward comparison and threshold determination without requiring complex calculation circuits. The intermediary transforms a potentially complex voltage-dependent control problem into a simpler voltage comparison task.
Solution Approach 2:
The variable reference voltage generator serves multiple functions: it provides the adaptive threshold reference, enables voltage-dependent current limiting, and simplifies the comparator logic. This multi-functionality reduces the need for separate control circuits for each function, thereby limiting the increase in overall device complexity while achieving adaptability.
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 solution enables the adaptive current limiter to automatically adjust its current trip point based on input voltage, preventing premature breakage at lower voltages and avoiding damage at higher voltages, thus ensuring reliable operation across a range of input voltages.
Implementation Method 1
Resistor RSENSE is coupled to negative VIN node 6 and to pass transistor 36 which acts as a circuit breaker at node 38. The purpose of resistor RSENSE is to sense the current I2 flowing between negative VIN node 6 and VOUT node 24 and produce a voltage VSENSE at node 38
Implementation Method 2
a variable reference voltage generator coupled to the power input, and which provides a variable reference voltage which is inversely proportional to the input voltage
Implementation Method 3
Comparator 40 is coupled to node 34 and to node 38 such that it compares voltage VSENSE to voltage V1. The output of comparator 40 is coupled to latch 42 indicating when the circuit should be broken or modified
Data Source
AI summary
An adaptive current limiter is coupled to a power source and which comprises a variable reference voltage generator which provides a variable reference voltage which is inversely proportional to the input voltage from the power source, which in certain embodiments is representative of the maximum allowable current level that may flow through a connected load at the present voltage provided by the power source given a fixed power limit. The current flow to the load is interrupted when the power level provided to the load exceeds predefined constant power and/or constant current limits.