Digital Temperature Sensor Gain Trimming With Single Capacitance
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Solution Overview
Problem
Existing digital temperature sensors are affected by non-ideal factors such as PVT variations and aging, leading to reduced precision and accuracy in temperature measurement.
Innovation Solution
A digital temperature sensor design that incorporates a gain factor α, unaffected by non-ideal factors, and allows for adjustable trimming, using a single capacitance to replace an array of capacitances, enhancing precision and reducing area occupation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an array of capacitances is used in the temperature sensor, then the gain can be adjusted, but the area occupation increases
Solution Approach 1:
The patent merges multiple capacitance values into a single capacitance element by utilizing different connection configurations (series/parallel arrangements) of the same physical capacitance. This allows the temperature sensor to achieve multiple gain values without requiring multiple separate capacitance components, thereby reducing the overall area occupation while maintaining gain adjustability.
2Measurement precision
If traditional temperature sensor designs are used, then the structure is simple, but the precision is reduced due to PVT variations and aging
Solution Approach 1:
The patent changes the operational parameters of the temperature sensor by introducing a controllable gain factor that can be adjusted based on operating conditions. This allows the sensor to compensate for PVT (process, voltage, temperature) variations and aging effects dynamically, thereby maintaining high measurement precision without requiring a fundamentally complex sensor structure.
Solution Approach 2:
The patent implements a feedback mechanism where the gain factor is adjusted based on detected operating conditions or calibration data. This feedback loop enables the sensor to automatically compensate for drift and variations, improving long-term precision without requiring overly complex hardware architecture.
3Measurement precision
If the gain factor is fixed, then the circuit is simpler, but the precision is affected by non-ideal factors and variations
Solution Approach 1:
The patent transitions from a fixed gain factor to a dynamic, adjustable gain factor that can be modified based on operating conditions. This dynamic approach allows the circuit to adapt to non-ideal factors and variations, improving detection accuracy. The implementation uses switching circuits controlled by digital signals, which add minimal complexity while enabling precise gain control.
Data Source
AI summary
First and second transistors produce a first signal indicating the voltage drop difference across the transistors and a second signal indicating the voltage drop across the second transistor. The first and second signals increase and decrease, respectively, with temperature sensed based on the first signal via a gain factor. An ADC coupled to the transistors produces a pulsed output bitstream with a duty cycle based on the first and second signals via the gain factor. A selection stage intermediate the transistors and the ADC alternates first and second cycles under control of the bitstream, to transfer to the ADC during the first and second cycles, first and second numbers of alternations of signal transfer phases, wherein the first and second signals, respectively, are transferred with alternate signs to the ADC. The gain factor is based on the ratio of the first to the second number of alternations.