Overcurrent Protection Circuit Using Single Comparator Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing overcurrent protection circuits face challenges in accurately detecting overcurrents due to temperature changes in semiconductor switches, leading to inaccurate current interruption and increased circuit complexity.
Innovation Solution
An overcurrent protection circuit with a load drive section, current detection section, addition and subtraction section, and control section, which uses an AD converter and current value calculation circuit to detect load current values, perform temperature correction, and determine overcurrent levels with a single comparator, thereby simplifying the circuit configuration and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple comparators are used to detect multiple threshold values for accurate overcurrent detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple threshold comparison operations into a single comparator by integrating the threshold values into the integration calculation. Instead of comparing current against multiple thresholds simultaneously with separate comparators, the system integrates current over time and compares the integrated value against a single threshold, combining multiple functions into one component.
Solution Approach 2:
The single comparator in the patent performs multiple comparison functions by comparing the integrated current value against a threshold that represents different overcurrent levels. The integration process itself serves as a multi-level detection mechanism, allowing one comparator to accomplish what would traditionally require multiple comparators.
2Measurement precision
If temperature correction is implemented to improve overcurrent detection accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines temperature correction functionality with the current detection and integration circuitry. The integration process inherently accounts for temperature effects by accumulating current over time, and the single comparator handles both the integration result and threshold comparison, merging temperature compensation with the main detection function.
Solution Approach 2:
The integration circuit automatically compensates for temperature effects through the accumulation process. By integrating current over time rather than using instantaneous comparisons, the system self-adjusts for temperature drift without requiring separate temperature sensors or correction circuits, as the integration process naturally smooths out thermal variations.
3Measurement precision
If digital circuits and peripheral circuits are used to calculate thermal change, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex digital calculation circuits with an analog integration process. Instead of using digital circuits to calculate thermal change and perform corrections, the system uses an operational amplifier-based integrator that naturally performs the mathematical integration of current over time, substituting mechanical/electrical integration for digital computation.
Solution Approach 2:
The patent changes the detection parameter from instantaneous current to integrated current over time. This parameter transformation allows temperature effects to be naturally accounted for in the time-domain integration process, eliminating the need for separate temperature calculation circuits while maintaining detection accuracy.
Data Source
AI summary
An overcurrent protection circuit includes a load drive section driving a load, a wire coupled with the load and the load drive section, a current detection section detecting a load current value of an electric current that flows to the load, an addition and subtraction section determining an addition and subtraction value based on the load current value and transmitting an integration result of addition and subtraction, a comparison circuit comparing the integration result with a threshold value, and a control circuit controlling the load drive section based on the comparison result. The addition and subtraction section includes an addition value determination circuit that determines an addition value in the addition and subtraction value based on the load current value and a function expression or information indicating a relationship between the load current value and the addition value.