Temperature Sensing Device Using Voltage Ratio for Low Power
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Solution Overview
Problem
Conventional temperature sensing devices are not suitable for systems using low power supply voltages, as they require high power to function effectively, which is a challenge in miniaturized and integrated semiconductor devices where low power designs are necessary.
Innovation Solution
A temperature sensing device that utilizes a temperature-voltage converter generating a zero temperature coefficient voltage and a negative temperature coefficient voltage, which are alternately outputted by a multiplexer, allowing a temperature sensor to calculate temperature using a ratio of these voltages without an analog-digital converter, thereby reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional temperature sensing devices are used, then temperature sensing function is provided, but power consumption is high
Solution Approach 1:
The patent replaces the conventional analog-digital converter with a voltage-time converter that uses capacitor charging/discharging mechanisms. This substitution eliminates the need for high-power analog-digital conversion circuits while maintaining temperature measurement functionality through timing-based measurement of voltage transitions.
Solution Approach 2:
The patent changes the measurement parameter from direct voltage comparison to time-based capacitor charging measurement. By measuring the time required for a capacitor to charge to a threshold voltage level, the system achieves accurate temperature sensing with significantly reduced power consumption compared to continuous analog-digital conversion.
2Measurement precision
If analog-digital converter is used for temperature measurement, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts and removes the analog-digital converter from the temperature sensing circuit, replacing it with a simpler voltage-time conversion mechanism using basic RC circuits and comparators. This extraction eliminates complex conversion circuits while preserving measurement precision through alternative timing-based measurement.
Solution Approach 2:
The patent uses a simplified timing circuit that copies the essential measurement function of the analog-digital converter without requiring its complex structure. The voltage-time converter replicates the measurement capability through capacitor charging time measurement, achieving the same precision with much simpler circuitry.
3Measurement precision
If high power supply voltage is used for temperature sensing, then sensing accuracy is maintained, but power consumption increases
Solution Approach 1:
The patent employs periodic charging and discharging of capacitors to perform temperature measurements. By using alternating phases of capacitor charging (to generate reference and measurement voltages) and discharging (to reset the circuit), the system achieves accurate sensing with low average power consumption, avoiding the need for continuously high power supply voltage.
Data Source
AI summary
A temperature sensing device includes a temperature-voltage converter that outputs a first voltage, having a zero temperature coefficient that does not vary with a temperature, and a second voltage having a negative temperature coefficient varying in inverse proportion to the temperature. A multiplexer alternately outputs the first voltage and the second voltage depending on a transition signal. A temperature sensor alternately receives the first voltage and the second voltage and senses the temperature depending on a ratio of the first voltage and the second voltage.