Temperature Sensor Threshold Voltage Compensation Circuit
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Solution Overview
Problem
Temperature sensors face inaccuracies due to threshold voltage shifts in the sensing transistor caused by manufacturing processes and environmental factors, affecting the frequency of the output signal and resulting in inaccurate temperature measurements.
Innovation Solution
The introduction of a second charge-discharge circuitry and compensation control circuitry in the temperature sensor, which decouples and couples the adjustment voltage during charging and discharging periods to isolate the leakage current from the threshold voltage, ensuring the frequency is not affected by the threshold voltage shift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensing transistor is used to detect temperature, then temperature sensing function is achieved, but threshold voltage shifts due to manufacturing and environmental factors cause measurement inaccuracies
Solution Approach 1:
The patent divides the charge-discharge process into two independent stages: a first charge-discharge circuitry that is insensitive to threshold voltage shifts, and a second charge-discharge circuitry that measures the actual temperature. By segmenting the measurement process, the system eliminates the influence of threshold voltage variations on the temperature reading, thereby resolving the contradiction between measurement precision and reliability.
Solution Approach 2:
The patent changes the operating parameters of the sensing transistor by applying different voltages during different stages. During the first stage, a first voltage is applied to make the transistor operate in a region where threshold voltage shifts do not affect the charge-discharge characteristics. During the second stage, a second voltage is applied to perform the actual temperature measurement. This parameter change strategy decouples the measurement from threshold voltage variations, improving both accuracy and reliability.
2Measurement precision
If threshold voltage shift is compensated by adjusting operating parameters, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The patent merges the threshold voltage compensation function and the temperature measurement function into a single integrated circuit structure. The first charge-discharge circuitry and the second charge-discharge circuitry share common components such as the sensing transistor, capacitors, and control logic. By combining these functions, the patent achieves accurate temperature measurement without significantly increasing device complexity, as the compensation mechanism is embedded within the existing circuit architecture rather than adding separate compensation circuits.
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 ensures that the leakage current and hence the temperature measurement accuracy are not affected by the threshold voltage shift, maintaining the accuracy of temperature measurements despite manufacturing and environmental variations.
Implementation Method 1
the sensing transistor in the temperature sensor generates different current signals in response to different temperatures
Implementation Method 2
The current signal controls the signal output of the temperature sensor by controlling the charging and discharging rate of the charge-discharge circuitry in the temperature sensor
Implementation Method 3
an oscillation circuitry, coupled to a first node and a signal output end, and configured to control the signal output end to output an oscillation signal under a control of the first node
Implementation Method 4
a switch circuitry, coupled to a power signal input end, the first node and the signal output end, and configured to control the power signal input end to be coupled to or decoupled with the first node under a control of the signal output end
Data Source
AI summary
A temperature sensor and a temperature detection method are provided. The temperature sensor includes an oscillation circuitry, a switch circuitry, a first charge-discharge circuitry, a sensing transistor, a second charge-discharge circuitry and a compensation control circuitry. The compensation control circuitry is coupled to a second end of the second charge-discharge circuitry, an adjustment voltage input end and a first control signal input end, and configured to: control the adjustment voltage input end to be decoupled with the second end of the second charge-discharge circuitry under a control of the first control signal input end in a charging period of a temperature detection stage; control the adjustment voltage input end to be coupled to the second end of the second charge-discharge circuitry under the control of the first control signal input end in a discharging period of the temperature detection stage.