Power Supply Controller Overcurrent Protection Circuit
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Solution Overview
Problem
Conventional power supply controllers using semiconductor switches as fuses face challenges in maintaining consistent overcurrent protection characteristics across varying ambient temperatures, leading to increased parts count and complexity when using temperature sensors.
Innovation Solution
A power supply controller configuration that includes a switching circuit, a protection circuit, and a characteristic setting circuit to establish a protection-current temperature characteristic line, ensuring the semiconductor switch's protection-current value remains within safe limits across temperature variations, similar to mechanical fuses, without the need for additional temperature sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is provided in each power supply path to detect the difference between ambient temperatures, then the protection accuracy is improved, but the parts count and device complexity are increased
Solution Approach 1:
The patent replaces the mechanical temperature sensing approach with a semiconductor-based solution. The control circuit uses the intrinsic temperature-dependent characteristics of the semiconductor switch element itself to detect temperature changes and adjust protection thresholds, eliminating the need for separate temperature sensors and reducing device complexity while maintaining protection accuracy
Solution Approach 2:
The semiconductor switch element serves dual functions: as the main switching component and as the temperature sensing element. By monitoring the switch's own electrical characteristics that change with temperature, the system achieves self-diagnosis and self-adjustment of protection parameters without requiring external sensing components
2Adaptability or versatility
If the fusing characteristic is set higher for lower ambient temperatures, then the protection range is improved, but the device complexity increases due to temperature compensation mechanisms
Solution Approach 1:
The control circuit dynamically adjusts the protection threshold parameter based on detected temperature changes. When ambient temperature decreases, the control circuit raises the protection threshold to allow higher currents; when temperature increases, it lowers the threshold. This parameter adaptation achieves wide protection range without complex mechanical compensation mechanisms
Solution Approach 2:
The protection characteristic is made dynamic rather than static. The control circuit continuously monitors temperature and real-time adjusts the overcurrent protection threshold accordingly, enabling the system to adapt to varying ambient conditions and maintain optimal protection across different temperature environments
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 configuration allows for simplified design with reduced parts count, maintaining effective overcurrent protection across temperature ranges, similar to mechanical fuses, while avoiding performance decline at high temperatures and ensuring reliable operation.
Implementation Method 1
The power supply controller controls current supply to the load by turning on and off the semiconductor switch element. Furthermore, the power supply controller uses the semiconductor switch element in place of a mechanical current fuse as a fuse for protecting the power supply path to the load from overcurrent etc.
Data Source
AI summary
If a power supply path is in an abnormal state, a power-supply-path protection circuit of a power supply controller inhibits a switching circuit that switches on/off power supply from a power source to a load from power supply, using data related to a protection-current temperature characteristic line set by a characteristic setting circuit. The protection-current temperature characteristic line has a characteristic in which a protection current value is constant corresponding to increase in an ambient temperature or a negative characteristic in which the protection current value reduces corresponding to increase in the ambient temperature. Within a temperature range equal to or lower than an supposed maximum ambient temperature around the power-supply-path, the protection-current temperature characteristic line and a power-supply-path temperature characteristic line have a relation that the protection-current value is equal to or lower than an allowable current value at an identical ambient temperature.