On-Chip Diode Temperature Sensor with Calibration Circuit
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Solution Overview
Problem
Integrated circuits face performance issues due to temperature variations, which are typically monitored using external temperature sensing devices that require large external components, occupying valuable board space and necessitating a more efficient on-chip temperature sensing solution.
Innovation Solution
An on-chip temperature sensing circuit using a diode with a feedback loop, including a comparator and logic circuitry, generates a digital code to determine temperature, and an additional calibration circuit adjusts for process, temperature, and supply voltage variations, minimizing external components and board space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If off-chip temperature sensors are used to monitor IC temperature, then temperature sensing capability is provided, but board space is occupied and external components are required
Solution Approach 1:
The patent merges the temperature sensing function into the IC chip itself by integrating a diode-based temperature sensing circuit with feedback loop, comparator, and logic circuitry on-chip. This eliminates the need for separate off-chip temperature sensors and reduces board space requirements while maintaining temperature monitoring capability.
Solution Approach 2:
The diode structure serves multiple functions: it acts as both a standard circuit component and a temperature sensing element. The same diode used for logic operations also provides temperature information through its voltage characteristics, eliminating the need for dedicated temperature sensing components.
2Measurement precision
If traditional temperature sensing diode with off-chip sensor is used, then temperature monitoring is achieved, but numerous external components and pins are required
Solution Approach 1:
The patent combines multiple functions (temperature sensing, signal comparison, logic processing) into a single integrated circuit block on the IC chip. The feedback loop, comparator, and logic circuitry are all implemented on-chip, eliminating the need for external sensors and reducing the number of required pins and external components.
Solution Approach 2:
The temperature sensing circuit is nested within the existing IC structure, utilizing the diode that is already part of the chip's logic circuitry. The sensing function is embedded within the existing device architecture rather than being added as a separate external component.
3Area of stationary object
If on-chip temperature sensing is implemented, then board space is reduced, but process, temperature, and supply voltage variations cause inaccuracies
Solution Approach 1:
The patent implements a feedback loop that continuously monitors the diode voltage and adjusts the measurement accordingly. The comparator compares the diode voltage against reference values, and the logic circuitry processes this feedback information to compensate for variations in process, temperature, and supply voltage, maintaining measurement accuracy despite environmental changes.
Solution Approach 2:
The patent compensates for variations by dynamically adjusting measurement parameters based on detected conditions. The logic circuitry modifies the interpretation of diode voltage readings based on feedback about process variations, temperature changes, and supply voltage fluctuations, thereby maintaining accurate temperature measurement across varying conditions.
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 effectively reduces board space requirements by integrating temperature sensing and calibration functions on-chip, providing accurate temperature measurement and compensating for inaccuracies caused by variations, thereby maintaining performance within desired specifications.
Implementation Method 1
The voltage across the diode varies with the temperature of the IC
Data Source
AI summary
Techniques are provided for sensing the temperature of an integrated circuit (IC). A diode is provided on an IC. The voltage across the diode varies with the temperature of the IC. A feedback loop is coupled around the diode to monitor the voltage across the diode. The feedback loop contains a comparator and logic circuitry that outputs a digital code. The digital code varies in response to changes in the diode voltage. The value of the digital code can be used to determine the temperature on the IC. Techniques are also provided for automatically calibrating a temperature sensing circuit to compensate for inaccuracies caused by variations in process, temperature, and supply voltage. A calibration circuit is added to the feedback loop in the temperature sensor. The calibration circuit generates an offset code that is used to adjust the digital code to compensate for variations in temperature, process, and supply voltage.