Sigma-Delta Digital Temperature Sensor for On-Chip Hot Spot Detection
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Solution Overview
Problem
Traditional temperature sensors placed on the back of high-power semiconductor chips fail to accurately detect internal temperature distributions, leading to ineffective temperature protection due to non-uniform hot spots.
Innovation Solution
A digital temperature sensor circuit incorporating a PTAT current source, sigma-delta modulation module, and digital filter that generates a digital modulation signal proportional to temperature, allowing for direct internal temperature detection and reduced power consumption by omitting the integration amplifier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a temperature sensor is placed on the back of the chip to detect temperature, then the detection structure is simple, but the temperature detection accuracy deteriorates due to inability to detect internal temperature distribution
Solution Approach 1:
The patent transitions from external back-side temperature sensing to internal temperature sensing by integrating the temperature sensor within the same chip substrate as the power device. This dimensional relocation enables direct measurement of internal temperature distribution, resolving the contradiction between structural simplicity and measurement accuracy.
Solution Approach 2:
The temperature sensor and power device are merged into a single integrated chip structure. The sensor is positioned adjacent to or within the power device footprint, allowing simultaneous measurement of internal temperature while maintaining compact design. This merging resolves the contradiction by achieving accurate internal temperature detection without significantly increasing overall device complexity.
2Device complexity
If traditional temperature sensing methods are used, then the circuit structure is simple, but the temperature protection effectiveness deteriorates due to inaccurate hot spot detection
Solution Approach 1:
The patent replaces traditional external mechanical temperature sensing with an integrated electronic temperature sensor that directly measures internal temperature. This substitution enables accurate hot spot detection, allowing the protection circuit to respond effectively to actual thermal conditions, thereby resolving the contradiction between circuit simplicity and protection reliability.
3Power
If an integration amplifier is used in the temperature sensor circuit, then the signal amplification is sufficient, but the power consumption increases
Solution Approach 1:
The patent extracts and removes the integration amplifier from the temperature sensor circuit, retaining only the essential differential amplifier. This extraction eliminates unnecessary power consumption while maintaining sufficient signal amplification capability, resolving the contradiction between amplification strength and energy efficiency.
Solution Approach 2:
The patent discards the redundant integration amplifier stage that consumes excessive power, recovering only the essential amplification function through a simplified differential amplifier design. This selective discarding and recovery resolves the contradiction by eliminating waste while preserving necessary functionality.
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
Improves temperature detection accuracy and reduces power consumption, enabling effective temperature protection and binary code conversion for digital processing, thus enhancing the application of temperature monitoring in high-power semiconductor devices.
Implementation Method 1
a proportional to the absolute temperature (PTAT) current source, generating a PTAT current proportional to absolute temperature
Implementation Method 2
the integrator converts the PTAT current into temperature voltage
Implementation Method 3
the analog-to-digital conversion unit compares the temperature voltage with a band gap reference voltage to generate a digital modulation signal
Data Source
AI summary
A digital temperature sensor circuit is disclosed. The digital temperature sensor circuit includes a proportional to the absolute temperature (PTAT) current source, generating a PTAT current proportional to absolute temperature; a sigma-delta modulation module, including an integrator, an analog-to-digital conversion unit, and a feedback digital-to-analog conversion unit; the integrator converts the PTAT current into temperature voltage; the analog-to-digital conversion unit compares the temperature voltage with a band gap reference voltage to generate a digital modulation signal with a duty ratio proportional to the temperature; the feedback digital-to-analog conversion unit adjusts the voltage input by the analog-to-digital conversion unit and controls the charging and discharging speed of the integrator; a digital filter, quantizing the digital modulation signal into a digital signal, and outputting the digital signal.