Temperature Sensor Calibration Circuit for PTAT Voltage Windowing
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Solution Overview
Problem
Existing temperature sensor calibration circuits in wireless communication systems, particularly in RF power amplifiers, face challenges in achieving high accuracy due to temperature variations, which can affect the linear performance and efficiency of power amplifiers and potentially damage hardware.
Innovation Solution
A calibration circuit for temperature sensors that includes a current source generating a temperature-independent reference current, a voltage window generator circuit, and a pedestal circuit, which together define a voltage window to accurately capture proportional to absolute temperature (PTAT) voltage outputs, and adjust reference voltages to cancel common mode offset errors, ensuring accurate temperature measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensor calibration is performed without temperature compensation, then the circuit complexity is reduced, but the measurement precision deteriorates due to temperature variations affecting sensor accuracy
Solution Approach 1:
The patent introduces a calibration circuit as an intermediary component that mediates between the temperature sensor and the measurement system. This calibration circuit includes reference voltage generators and adjustment mechanisms that compensate for temperature effects, thereby improving measurement precision without requiring fundamental changes to the sensor itself.
Solution Approach 2:
The patent employs parameter changes by adjusting reference voltages and calibration parameters based on temperature conditions. The calibration circuit dynamically modifies electrical parameters (voltages, currents) to compensate for temperature-induced variations in sensor characteristics, maintaining measurement accuracy across different temperature ranges.
2Adaptability or versatility
If a wide voltage window is used to capture PTAT voltage outputs, then the measurement range is improved, but the manufacturing precision deteriorates due to increased sensitivity to voltage variations
Solution Approach 1:
The patent implements dynamics by making the voltage window adjustable rather than fixed. The calibration circuit can dynamically adjust the voltage window width and position based on operating conditions and temperature ranges, allowing the system to adapt to different measurement requirements while maintaining precision through controlled adjustment mechanisms.
Solution Approach 2:
The patent applies segmentation by dividing the voltage measurement range into multiple calibrated segments or zones. Each segment can be independently calibrated with appropriate reference voltages, allowing the system to maintain high precision within each segment while covering a wide overall temperature range through cumulative segmentation.
3Measurement precision
If offset voltage compensation is applied to cancel common mode errors, then the measurement precision is improved, but the device complexity increases due to additional compensation circuits
Solution Approach 1:
The patent implements self-service by designing the calibration circuit to automatically generate and apply offset voltage compensation without external intervention. The circuit self-calibrates by detecting common mode errors and generating compensating voltages internally, improving measurement precision while minimizing the need for external compensation components.
Solution Approach 2:
The patent merges the offset compensation function with the existing calibration circuit architecture. Rather than adding separate compensation circuits, the patent integrates offset adjustment capabilities into the voltage reference and calibration blocks, achieving error cancellation while reducing overall device complexity through functional consolidation.
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 proposed solution improves the accuracy of temperature sensing to ±3°C over a 100°C range, enabling precise bias voltage control and preventing hardware damage by accurately monitoring operating temperatures in RF power amplifiers.
Implementation Method 1
a current source configured to generate a temperature independent reference current
Implementation Method 2
a width of the voltage window includes a range of proportional to absolute temperature (PTAT) voltage outputs of a temperature sensor
Implementation Method 3
a pedestal circuit configured to generate an offset voltage that increases or decreases the first and second reference voltages... the offset voltage is configured to cancel a common mode offset error
Data Source
AI summary
Embodiments of a device and method are disclosed. In an embodiment, a calibration circuit for a temperature sensor circuit includes a current source configured to generate a temperature independent reference current and further includes a voltage window generator circuit. The voltage window generator circuit is configured to generate a voltage window for the temperature sensor circuit using at least the temperature independent reference current. The voltage window is defined by a first reference voltage and a second reference voltage. The voltage window generator circuit is further configured to control a width of the voltage window to include a range of proportional to absolute temperature (PTAT) voltage outputs of a temperature sensor in the temperature sensor circuit.