Dynamic Current Limiting for Portable LMR Devices
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Solution Overview
Problem
Portable communication devices face challenges in managing excessive transient current demands, which can reset the device and disrupt communication, especially when incorporating non-LMR features like LTE and GPS, due to increased power loading, necessitating improved power management that prioritizes mission-critical functions without increasing size, cost, or weight.
Innovation Solution
The implementation of a method and apparatus that dynamically adjusts current limiting through a comparator bank and logic interface, or a single comparator with a finite state machine, to control high current loads during transmit events, prioritizing mission-critical LMR functions while scaling back non-essential peripherals, ensuring seamless operation and preventing device resets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional non-LMR features (LTE, GPS, WiFi) are added to expand device functionality, then device versatility is improved, but transient current demands increase causing device resets and communication loss
Solution Approach 1:
The patent implements dynamic current limiting that adjusts in real-time based on battery voltage conditions. The system transitions from static current limiting to a dynamic approach where the current limit is adjusted based on detected voltage drops, allowing the device to adapt functionality based on available power while maintaining communication reliability
Solution Approach 2:
The system changes the current limiting parameter dynamically based on battery voltage conditions. When voltage drops indicate excessive current demand, the system adjusts the current limit threshold to prevent device resets, thereby maintaining communication continuity while allowing expanded functionality
2Use of energy by moving object
If more battery cells are added to meet increased power demands, then power capacity is improved, but device size, cost, and weight increase
Solution Approach 1:
The patent applies partial current limiting only to non-essential peripheral functions when voltage drops are detected, rather than limiting all functions. This selective approach allows the device to maintain operation with existing battery capacity by dynamically managing power distribution, avoiding the need for additional battery cells
Solution Approach 2:
The system dynamically adjusts current limiting parameters based on real-time voltage monitoring, optimizing power utilization from existing battery cells without requiring increased power capacity through additional cells
3Reliability
If current limiting is applied to prevent transient power loading, then device reliability is improved, but mission critical function operation may be compromised
Solution Approach 1:
The patent implements selective current limiting that targets specific non-essential peripheral functions rather than applying uniform current limiting across all device functions. This allows mission-critical LMR communication functions to maintain full power operation while non-essential features are dynamically limited to prevent device resets
Solution Approach 2:
The system continuously monitors battery voltage and provides feedback to adjust current limiting in real-time. When voltage drops indicate excessive current demand, the feedback mechanism triggers selective current limiting on non-essential functions, preventing device resets while preserving mission-critical function operation
Data Source
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AI summary
A battery operated portable communication device provides converged functionality while avoiding resets to the device. Composite logic circuitry formed of at least one comparator and a logic interface controls current limiting to a primary load formed of high power land mobile radio (LMR) devices and programming to secondary loads formed of non-LMR peripherals. At least one current limit control signal is used to control current to the primary load under high current mode operations. Another control signal provides an interruption alert to a slave processor for controlled programming of the secondary loads during the high current operations of the primary load. Current to the primary load is restored while the secondary load is interrupted. Operation of secondary load processes is resumed when the primary load ceases high power operation.