Thermal Sensor Circuit with Analog Chopping and DEM for ICs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing thermal sensors for integrated circuits (ICs) face inaccuracies in temperature measurement due to factors like reduced supply voltages, process variations, flicker noise, and parasitic resistance, leading to unreliable overheating detection and increased power consumption.
Innovation Solution
A thermal sensor circuit using two sensing diodes driven by current sources with analog chopping and dynamic element matching (DEM) to reduce noise and process variations, coupled with an analog-to-digital converter (ADC) for accurate digital temperature readings, independent of parasitic resistances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional thermal sensors are used in ICs, then temperature sensing is provided, but measurement accuracy deteriorates due to parasitic resistance, process variations, and flicker noise
Solution Approach 1:
The patent replaces traditional analog thermal sensing mechanisms with a digital-based sensing approach. A digital thermometer circuit is integrated into the IC die, using digital logic elements (D-flip flops, multiplexers, counters) to sense and process temperature information. This substitution of digital for analog/mechanical sensing eliminates the impact of parasitic resistance and analog noise, directly resolving the measurement accuracy and reliability contradiction.
Solution Approach 2:
The patent introduces a temperature sensing diode as an intermediary element that converts temperature information into electrical signals readable by the digital circuit. The diode's forward voltage characteristic varies with temperature, serving as a mediator between the thermal environment and the digital sensing circuitry. This intermediary approach allows accurate temperature measurement without direct electrical contacts that would introduce parasitic resistance.
2Temperature
If thermal management devices are continuously operated to prevent overheating, then temperature control is maintained, but power consumption increases
Solution Approach 1:
The patent implements a feedback-based thermal management system where the digital thermometer continuously monitors the IC die temperature and provides real-time temperature data to the control logic. Based on this feedback, the system can dynamically adjust cooling device operation (such as fans or heat sinks) only when temperature thresholds are exceeded, rather than continuous operation. This feedback mechanism maintains temperature control while minimizing unnecessary power consumption.
Solution Approach 2:
The patent employs periodic temperature sampling and threshold-based activation of thermal management devices. Instead of continuous operation, the cooling system is activated periodically or on-demand based on temperature readings. The digital thermometer takes periodic measurements, and when the temperature exceeds a predetermined threshold, the thermal management device is activated for a controlled duration to bring the temperature back within acceptable ranges, thereby reducing overall power consumption while maintaining effective temperature control.
3Productivity
If IC density and clock speed are increased to improve performance, then productivity increases, but heat generation and overheating risk increase
Solution Approach 1:
The patent integrates a digital thermometer circuit directly into the IC die during manufacturing, enabling temperature monitoring to begin immediately upon IC operation. This preliminary action of having temperature sensing capability built-in from the start allows the system to proactively monitor and manage heat generation as IC density and clock speed increase, rather than adding external monitoring later. The early detection capability enables preventive thermal management before overheating occurs.
Solution Approach 2:
The patent implements real-time temperature feedback monitoring using the integrated digital thermometer. As IC density and clock speed increase and generate more heat, the thermometer continuously provides feedback on the actual die temperature. This feedback enables dynamic adjustment of operating parameters, clock speeds, or activation of thermal management devices to maintain safe operating temperatures, allowing the system to sustain high productivity while preventing overheating through active temperature control.
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 more accurate temperature measurements, reducing noise and power consumption by filtering out DC errors and minimizing the impact of parasitic resistances, enabling precise thermal management in ICs.
Implementation Method 1
Voltage/current characteristics of the diode may change depending upon temperature of the IC
Data Source
AI summary
A thermal sensor is provided that includes a front-end component, an analog-to-digital converter and a digital backend. The front-end component including an array of current sources, a dynamic element matching (DEM) device, an analog chopper and two diodes to sense temperatures on the die. The front-end component to provide analog signals at two output nodes based on currents through the two diodes. The analog-to-digital converter to receive the analog signals from the front-end component and to provide an output signal. The digital backend to receive the output signal from the analog-to-digital converter and to provide a calculated temperature.