Battery Charger Over-Current Detection Using Resistive Sensing
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Solution Overview
Problem
Existing battery chargers controlled by microprocessors often have insufficient response times to handle critical anomalies like large surges in charge current, which can cause damage to batteries if not addressed promptly.
Innovation Solution
A method involving a resistive element and a comparator to sense charge current, generating a trigger signal when voltage exceeds a predetermined value, and coupling this signal to a microprocessor to initiate an over-current handling routine, ensuring prompt action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a microprocessor is used to control battery charging, then the charger can handle multiple functions and battery chargers, but the response time to critical anomalies becomes insufficient
Solution Approach 1:
The system is divided into two independent parts: a microprocessor for handling multiple charging functions and a separate hardware circuit (comparator + resistive element) dedicated solely to current monitoring. This segmentation allows the microprocessor to maintain its multi-functional role while the dedicated hardware circuit provides immediate response to critical anomalies without being burdened by other tasks.
Solution Approach 2:
A hardware intermediary circuit consisting of a resistive element and comparator is introduced between the power source and the microprocessor. This intermediary continuously monitors charge current and generates interrupt signals for critical anomalies, acting as a dedicated watchdog that bridges the gap between the power source and the microprocessor's control logic.
2Productivity
If the microprocessor shares processing power among multiple battery chargers, then system utilization is improved, but the response time to critical anomalies in each charger deteriorates
Solution Approach 1:
The current monitoring circuit serves itself by autonomously detecting over-current conditions and generating interrupt signals without requiring microprocessor intervention. The resistive element and comparator form a self-contained monitoring system that independently handles critical anomaly detection, freeing the microprocessor to focus on general charging management tasks.
Solution Approach 2:
The hardware monitoring circuit performs preliminary detection of critical anomalies before they can cause damage. By continuously monitoring current through the resistive element and being ready to trigger interrupts, the system prepares for potential over-current events in advance, ensuring immediate response capability regardless of microprocessor workload.
3Reliability
If hardware circuitry is added for continuous current monitoring, then response time to critical anomalies is improved, but device complexity increases
Solution Approach 1:
The critical anomaly detection function is extracted from the microprocessor and implemented as a separate, simple hardware circuit. This extraction removes the complexity of software-based monitoring from the microprocessor's task list and replaces it with a dedicated but structurally simple voltage comparison circuit that only needs to detect when voltage exceeds a threshold.
Solution Approach 2:
The monitoring approach changes from measuring current directly (complex) to measuring voltage across a known resistive element (simple). By converting the current measurement problem into a voltage comparison problem, the system achieves reliable fault detection using a simple comparator circuit with a single threshold comparison, minimizing added complexity.
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 timely intervention in critical anomalies, preventing damage to batteries by enabling the microprocessor to initiate appropriate handling routines, such as disabling power to the charging station, thereby enhancing safety and protecting batteries.
Implementation Method 1
sensing a charge current applied to a battery with a resistive element. The method includes measuring a voltage across the resistive element
Data Source
AI summary
A method of fault detection for battery chargers includes sensing a charge current applied to a battery with a resistive element. The method includes measuring a voltage across the resistive element. The method includes generating a trigger signal when the measured voltage across the resistive element exceeds a predetermined value. The method includes generating from the trigger signal an interrupt signal for a microprocessor. The method includes initiating an over-current handling routine in the microprocessor.