Current Limit Stabilization Circuit for Portable Transmitters
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Solution Overview
Problem
Portable communication devices face challenges in managing variations in transmit current associated with DC-to-DC converters, leading to resets or loss of communication, particularly in public safety environments where size, cost, and weight considerations are critical, and mission-critical functionality must be retained.
Innovation Solution
A method and apparatus that dynamically stabilizes current limiting relative to input voltage of a DC-to-DC converter in a portable communication device, using a current limit stabilization circuit that generates a variable stabilizing reference voltage proportional to the supply voltage, allowing for reduced current variation and improved power management across different operating platforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a DC-to-DC converter is used to supply a transmitter in a portable communication device, then power management capability is improved, but current variations cause resets or loss of communication
Solution Approach 1:
The patent implements a feedback mechanism where the actual current drawn by the DC-to-DC converter is monitored and compared against a target current. Based on this comparison, the transmit power is dynamically adjusted to maintain the target current, thereby preventing current variations that would cause resets or communication loss while preserving the power management benefits of the DC-to-DC converter
Solution Approach 2:
The patent dynamically changes the transmit power parameter based on the actual current draw of the DC-to-DC converter. By adjusting the transmit power in response to converter performance, the system maintains stable operating conditions and prevents communication disruptions while utilizing the DC-to-DC converter's power management capabilities
2Power
If more battery cells are added to increase power capacity, then power availability is improved, but cost, size, and weight increase
Solution Approach 1:
The patent employs dynamic power management by continuously monitoring the DC-to-DC converter's current draw and adjusting transmit power in real-time. This dynamic approach allows the system to maximize power utilization from the existing battery cells, extracting more effective power capacity without adding physical battery mass, thereby improving power availability while maintaining acceptable device weight
Solution Approach 2:
The system dynamically adjusts transmit power parameters based on converter performance metrics, enabling more efficient power extraction from the existing battery cells. This parameter optimization allows the device to achieve higher effective power output from the same battery configuration, avoiding the need to add more battery cells and the associated weight increase
3Power
If more battery cells are added to increase power capacity, then power availability is improved, but cost increases
Solution Approach 1:
The patent implements dynamic power management that optimizes the utilization of existing battery cells through real-time monitoring and adjustment of transmit power. This dynamic optimization enables the system to achieve higher effective power capacity from the same battery configuration, eliminating the need to manufacture devices with additional battery cells and the associated increased cost
4Device complexity
If fixed reference current limiting is used, then current limiting is simplified, but current variation increases by approximately 700 mA
Solution Approach 1:
The patent replaces fixed reference current limiting with a feedback-based dynamic current limiting approach. The actual current drawn by the DC-to-DC converter is monitored and fed back to adjust the current limit dynamically, maintaining stable current operation across varying conditions while preventing the approximately 700 mA current variation that would occur with fixed reference limiting
Solution Approach 2:
The patent dynamically changes the current limit parameter based on the DC-to-DC converter's operating conditions and actual current draw. This dynamic parameter adjustment maintains stable current operation and prevents excessive current variation, improving upon the fixed reference approach while managing system complexity through structured control logic
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 reduces current variation by approximately 700 mA, providing more predictable and improved performance compared to fixed reference current limiting methods, thereby enhancing battery life and managing transmit features under different loading conditions.
Implementation Method 1
A DC-to-DC converter may be incorporated within a portable communication device to operate as a power supply for a transmitter
Implementation Method 2
a current limit stabilization circuit that generates a variable stabilizing reference voltage proportional to the supply voltage
Data Source
AI summary
A battery operated portable communication device is provided with improved transmitter current limit stabilization via a current limit stabilization circuit operatively coupled to the battery and a DC-to-DC converter of the transmitter. The current limit stabilization circuit provides a variable stabilizing reference voltage which is directly proportional to the supply voltage. The current limit stabilization circuit generates a voltage limit output voltage that controls both the power to the transmitter (120) and limits current to the transmitter.