Battery Over-Current Detection Circuit with Dynamic Reference Voltage
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Solution Overview
Problem
Conventional battery devices experience reduced accuracy in over-current detection due to varying resistance values of Nch charging/discharging control field effect transistors with changes in voltage and temperature, leading to safety concerns.
Innovation Solution
A charging/discharging control circuit with a reference voltage circuit including a constant current circuit, a resistor, and a transistor with varying resistance, connected to both ends of the secondary cell, to match the dependency of over-current detection voltage and resistance value on voltage and temperature, improving the accuracy of over-current detection current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a constant reference voltage is used in the over-current detection circuit, then the circuit design is simple, but the over-current detection current value fluctuates due to resistance changes of the Nch charging/discharging control field effect transistor with voltage and temperature
Solution Approach 1:
The patent changes the reference voltage parameter dynamically based on temperature and voltage conditions. The reference voltage circuit includes a transistor whose resistance varies with temperature, and a voltage detection circuit that adjusts the reference voltage according to the secondary cell voltage, thereby compensating for resistance changes in the charging/discharging control transistors and maintaining accurate over-current detection
Solution Approach 2:
The patent implements a feedback mechanism where the voltage detection circuit continuously monitors the voltage of the secondary cell and adjusts the reference voltage accordingly. The over-current detection circuit uses this feedback to compensate for resistance variations in the charging/discharging control transistors, ensuring accurate current detection across different operating conditions
2Ease of operation
If the reference voltage circuit does not compensate for temperature and voltage changes, then the circuit operation is simple, but the safety of the battery device is reduced due to inaccurate over-current detection
Solution Approach 1:
The reference voltage circuit dynamically adjusts its output voltage based on temperature and cell voltage parameters. By changing the reference voltage parameter in response to environmental conditions, the circuit maintains accurate over-current detection without requiring complex operational procedures, thus preserving both ease of operation and safety
Solution Approach 2:
The patent transforms the static reference voltage into a dynamic parameter that automatically adapts to changing conditions. The voltage detection circuit and temperature-compensated reference voltage circuit work together to create a dynamic system that maintains safety across varying operating conditions without requiring manual intervention
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 enhances the accuracy of over-current detection current values and increases the safety of battery devices by maintaining a constant over-current detection current even with changes in voltage and temperature.
Implementation Method 1
the resistance value of the Nch charging/discharging control field effect transistor varies with the changes in voltage of the secondary cell and temperature
Implementation Method 2
A reference voltage circuit of an over-current detection circuit is configured to include a constant current circuit, a resistor, and a transistor having a resistance value that varies with a voltage of a secondary cell
Data Source
AI summary
There is provided a battery device in which the accuracy of an over-current detection current value is high to have high safety. In a charging/discharging control circuit, a reference voltage circuit of an over-current detection circuit is configured to include a constant current circuit, a resistor, and a transistor having a resistance value that varies with a voltage of a secondary cell, that are connected to both ends of the secondary cell, and outputs, as a reference voltage, a voltage that is generated due to the flowing of a current of the constant current circuit to the resistor and the transistor.