On-Chip Temperature Sensor Circuit Using Diode and PTAT Weighting
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Solution Overview
Problem
Existing temperature sensors are not sufficiently accurate for certain applications, particularly in wireless devices, and fail to provide reliable temperature measurements within desired temperature ranges.
Innovation Solution
A temperature sensor circuit is developed, incorporating a voltage generator circuit with a diode circuit and a proportional to absolute temperature (PTAT) circuit, along with scalar circuits to weight and combine voltages, and heaters integrated into the temperature sensor die to modify temperature for testing, allowing for more accurate temperature measurement and correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing temperature sensors are used, then device complexity is reduced, but measurement precision is insufficient
Solution Approach 1:
The patent combines a diode circuit and a PTAT circuit into a unified temperature sensor structure, where both circuits share common components such as current sources and transistors. This merging approach achieves high measurement precision through voltage comparison while avoiding the complexity of completely separate circuits.
Solution Approach 2:
The temperature sensor circuit performs multiple functions: it generates diode voltage, generates PTAT voltage, compares voltages to determine temperature, and provides temperature compensation signals. This multi-functionality reduces overall device complexity while maintaining high measurement precision.
2Area of stationary object
If temperature sensors are integrated on-chip, then device compactness is improved, but measurement precision may deteriorate
Solution Approach 1:
The patent implements a nested structure where the PTAT circuit is integrated within the same chip as the diode circuit, with shared current sources and transistors. This nesting achieves compact on-chip integration while maintaining measurement precision through careful layout and matching of critical components.
Solution Approach 2:
The patent applies local quality by ensuring that critical matching components (transistors Q1-Q4, diodes D1-D2) are placed in close proximity with identical geometric dimensions and material properties, while non-critical components can be more loosely integrated. This localized precision maintains measurement accuracy despite overall chip integration.
3Measurement precision
If multiple circuit elements are used to improve accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent uses preliminary action by pre-matching the geometric dimensions and material properties of critical components during fabrication, and by pre-establishing the current mirror relationships in the PTAT circuit. This preliminary preparation reduces the need for additional complexity in component selection and assembly, achieving high precision with a manageable number of elements.
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 provides a more accurate and compact temperature sensor with improved yield, reducing variation in output voltage and enhancing the reliability of temperature measurements, resulting in better performance and cost reduction.
Implementation Method 1
The diode circuit may be configured to generate a diode voltage
Implementation Method 2
the proportional to absolute temperature circuit may be configured to generate a proportional to absolute temperature voltage
Implementation Method 3
a plurality of heaters distributed among the plurality of circuit elements and configured to modify a temperature of the temperature sensor when provided with a current
Data Source
AI summary
A diode voltage from a diode circuit can be combined with a proportional to absolute temperature (PTAT) voltage generated by a PTAT circuit to determine a temperature sensor voltage. This temperature sensor voltage may correspond to a temperature of a circuit or a localized temperature. By determining the temperature sensor voltage using a combination of a PTAT voltage and diode voltage, it is possible to remove or a PTAT circuit used to generate a bandgap voltage, which may shrink the temperature sensor and increase the accuracy of the temperature sensor circuit.