On-Die Temperature Sensor Calibration via Off-Die Current Biasing
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Solution Overview
Problem
Conventional temperature measurement systems for integrated circuit (IC) dies often result in inaccurate readings due to discrepancies between ambient calibration temperatures and actual die temperatures during operation.
Innovation Solution
A method involving an IC die with a temperature sensor, amplifier, current mirror, and disable circuit, where an off-die current source biases diodes to generate a voltage related to the die's temperature, allowing for accurate temperature determination and correction using a stored difference between two calibrated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the entire IC die is subjected to a known ambient temperature for calibration, then the calibration process can be performed, but the temperature measurement accuracy deteriorates due to the difference between ambient temperature and actual die temperature
Solution Approach 1:
A heating element is introduced as an intermediary component integrated within the IC die to directly heat the die substrate. This mediator enables independent control of die temperature separate from ambient temperature, allowing the die to be heated to a known temperature without requiring the entire packaging environment to be heated, thus resolving the contradiction between calibration simplicity and measurement accuracy
Solution Approach 2:
The patent changes the temperature parameter control approach by using an on-die heating element to independently control and vary the die temperature during calibration. Instead of relying on ambient temperature changes, the system actively controls the die temperature parameter through the heating element, enabling accurate calibration at multiple known temperature points while maintaining measurement precision
2Adaptability or versatility
If a temperature sensor is integrated within the IC die, then temperature determination during operation is enabled, but measurement accuracy deteriorates due to process variations and temperature gradients
Solution Approach 1:
The system implements feedback by using the integrated temperature sensor to continuously monitor die temperature during operation. The measured temperature is fed back to a controller that adjusts the heating element in real-time, enabling closed-loop temperature control that compensates for process variations and maintains measurement accuracy despite manufacturing tolerances
Solution Approach 2:
The patent applies preliminary action by performing calibration procedures before the IC die is shipped to customers. During calibration, the heating element and temperature sensor are tested together under controlled conditions, and calibration data is stored in non-volatile memory. This preliminary characterization compensates for process variations that will exist during actual operation, improving measurement precision without requiring complex real-time corrections
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 approach provides more accurate temperature measurements by controlling the applied current and diode characteristics, enabling precise temperature determination and correction, thereby improving the reliability of temperature sensing in IC dies.
Implementation Method 1
an off-die current source biases diodes to generate a voltage related to the die's temperature
Data Source
AI summary
A system may include biasing of diodes of a temperature sensor disposed in an integrated circuit die using a current from an off-die current source, generation of a voltage based on the current and a temperature of the integrated circuit die, and determination of a first temperature based on the voltage. Such a system may further include amplification of the voltage using an oscillator and a chopper stabilizer, determination of a first amplified voltage associated with a first state of the oscillator and a second amplified voltage associated with a second state of the oscillator, and determination of a third voltage based on the first amplified voltage and the second amplified voltage, wherein determination of the first temperature based on the voltage comprises determination of the first temperature based on the third voltage.