Bandgap Temperature Sensor Offset Compensation Trimming
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Solution Overview
Problem
Existing electronic thermometers face challenges in accurately measuring temperature due to circuit non-idealities and offset voltage issues, which degrade performance and accuracy.
Innovation Solution
A temperature measurement circuit with a bandgap circuit that includes an amplifier with offset voltage compensation using trimming bits, providing first and second voltages related to the temperature, and a measuring circuit that derives temperature measurements from these voltages, immune to semiconductor fabrication process variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If offset voltage compensation using trimming bits is implemented, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by performing offset voltage compensation before temperature measurement through a calibration phase. Trimming bits are pre-adjusted to compensate for offset voltages using test voltages that simulate measurement conditions, storing the compensated values for subsequent measurements. This preliminary compensation eliminates the need for complex real-time offset correction during actual temperature sensing.
Solution Approach 2:
The patent uses an intermediary approach by introducing test voltages as mediators to characterize and compensate for offset voltages. These test voltages, generated by the bandgap circuit at known temperature conditions, serve as intermediaries to determine trimming bit values that will cancel out offset effects during actual measurements, simplifying the overall measurement system.
2Reliability
If bandgap circuit with offset compensation is used, then reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements self-service by enabling the temperature measurement circuit to automatically compensate for its own offset voltages and non-idealities. The bandgap circuit generates test voltages that characterize its own offset behavior, and the trimming mechanism automatically adjusts to cancel these offsets, making the system self-correcting and reducing dependence on high manufacturing precision.
Solution Approach 2:
The patent uses feedback by measuring test voltages generated by the bandgap circuit and using these measurements to determine appropriate trimming bit values. This feedback loop allows the system to characterize its own offset voltages and non-idealities, then apply compensation to improve reliability without requiring extremely tight manufacturing tolerances.
Data Source
AI summary
An apparatus includes a temperature measurement circuit. The temperature measurement circuit includes a bandgap circuit including an amplifier having an offset voltage that is compensated by using a set of trimming bits. The bandgap circuit provides first and second voltages related to a temperature to be measured. The temperature measurement circuit further includes a measuring circuit coupled to receive the first and second voltages. The measuring circuit further includes a comparator coupled to receive the first and second voltages, wherein the measuring circuit derives a temperature measurement from the first and second voltages.