Temperature Detection Circuit External Resistor Accuracy
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Solution Overview
Problem
Conventional over-temperature detection circuits in energy storage elements, such as batteries, face accuracy issues due to resistance variation in internal resistors and increased power consumption from leakage currents, leading to degraded detection signals.
Innovation Solution
A temperature detection circuit with an external resistor and an integrated circuit (IC) chip, where the IC maintains a constant current ratio between the sensor and the resistor, improving accuracy by reducing resistance variation and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If internal resistors are used in the temperature detection circuit, then the circuit can be integrated onto the IC chip, but the resistance variation in different chips or doped regions degrades the detection accuracy
Solution Approach 1:
The patent extracts the resistor from the IC chip and places it externally. The IC chip now includes only the sensor and comparator, while the resistor is positioned outside the chip. This extraction eliminates the resistance variation problem associated with internally fabricated resistors, as external resistors can be selected with tighter tolerance values, thereby improving temperature detection accuracy while maintaining circuit integration through the chip's sensor and comparator components
Solution Approach 2:
The patent introduces an external resistor as an intermediary element between the sensor and the comparator. This external resistor serves as a stable reference that mediates the temperature detection process, providing a consistent resistance value that is not subject to the manufacturing variations inherent in internally fabricated resistors. The intermediary resistor enables accurate temperature detection by providing a stable reference point for the comparator to compare against the sensor output
2Use of energy by moving object
If the resistor resistance is increased to reduce current consumption, then power consumption decreases, but the voltage change of the temperature sense voltage decreases, degrading detection accuracy
Solution Approach 1:
The patent changes the resistance parameter of the external resistor to an optimized value that balances power consumption and detection accuracy. Rather than using very high resistance values that would minimize power consumption but degrade signal voltage, the external resistor is selected with a moderate resistance value that maintains sufficient voltage change across the sensor while keeping current consumption acceptable. This parameter optimization allows the circuit to achieve both low power consumption and high detection accuracy simultaneously
3Measurement precision
If external resistors are used to adjust resistance errors, then detection accuracy improves, but the chip size and cost increase
Solution Approach 1:
The patent extracts the resistor from the IC chip structure and positions it externally. This extraction eliminates the need to allocate additional chip area for resistor fabrication, as the external resistor is mounted separately on the circuit board or package. The IC chip itself remains compact, containing only the essential sensor and comparator circuits, while the external resistor provides the necessary resistance function without contributing to chip size increase
Solution Approach 2:
The patent uses a discrete external resistor component that replicates the resistance function previously attempted to be implemented internally. This external resistor copy provides the same electrical function with superior performance characteristics, including tighter tolerance and temperature stability, while avoiding the manufacturing complexity and area requirements of integrating high-precision resistors directly into the chip structure
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 enhances the accuracy of temperature detection and reduces power consumption by using an external resistor with less resistance variation, effectively protecting energy storage elements from over-temperature conditions.
Implementation Method 1
a negative temperature coefficient (NTC) thermistor 130 externally coupled to the chip 110 via a dedicated analog NTC pin. The thermistor 130 can sense temperature of, e.g., a battery pack, and can vary resistance of the thermistor 130 when the temperature changes.
Data Source
AI summary
A temperature detection circuit includes a sensor, an integrated circuit (IC) chip, and a resistor. The sensor is operable for sensing a temperature. The IC chip can compare a sense voltage indicative of the temperature with a threshold voltage indicative of a temperature threshold to determine a temperature condition. The IC chip has a substantially constant parameter. The resistor is externally coupled to the IC chip. The IC chip maintains a current ratio, including a ratio of a first current flowing through the sensor to a second current flowing through the resistor, equal to the substantially constant parameter.