Reverse Biased PN Junction Temperature Sensor
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Solution Overview
Problem
Existing temperature sensors integrated in electronic circuits face challenges such as high consumption, noise, and precision errors due to the need for bipolar components and reference value generation, which are not universally applicable and introduce undesirable consumption levels.
Innovation Solution
An integrated electronic device utilizing a reverse biased PN junction with variable capacitance, compared to a reference capacitance, to detect temperature variations through a switched capacitor operational amplifier, providing a direct voltage output with zero current consumption and simple structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bipolar components and reference value generation circuits are used for temperature sensing, then temperature detection capability is achieved, but current consumption increases and noise is introduced
Solution Approach 1:
The patent extracts only the essential temperature sensing function from complex bipolar circuits and reference value generation systems. By using a simple PN junction diode whose forward voltage drop varies with temperature, the invention eliminates unnecessary conditioning and amplification stages, achieving temperature detection with minimal current consumption and without the noise introduced by complex reference circuits.
Solution Approach 2:
The PN junction diode inherently provides temperature-dependent voltage characteristics that can be directly measured. The diode's forward voltage drop self-adjusts with temperature changes, eliminating the need for external reference value generation circuits and complex signal conditioning, thereby reducing current consumption while maintaining detection precision.
2Measurement precision
If bipolar components are used for temperature sensing, then temperature detection is enabled, but device complexity increases due to MOS technology incompatibility
Solution Approach 1:
The PN junction diode is a universal component that can be easily integrated into MOS technology circuits without requiring specialized bipolar components. This universal approach allows temperature sensing to be implemented in standard CMOS processes, reducing device complexity and improving compatibility with modern digital systems while maintaining adequate temperature detection precision.
3Measurement precision
If base-emitter voltage variation is used for temperature sensing, then temperature detection is achieved, but noise increases due to reference value comparison requirements
Solution Approach 1:
The patent removes the noisy reference value generation and comparison circuits from the temperature sensing system. By directly measuring the PN junction diode's forward voltage drop, which inherently varies with temperature, the invention eliminates the sources of noise associated with band-gap reference circuits and complex signal processing, achieving quieter temperature detection.
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 solution offers precise temperature sensing with zero current consumption, reduced noise, and easy integration in digital systems, overcoming the limitations of existing technologies by using a capacitive bridge with a compensation diode to cancel out leakage currents.
Implementation Method 1
a reverse biased PN junction has an equivalent capacitance variable in a known way with temperature
Data Source
AI summary
A method of sensing a temperature includes providing a voltage to reverse bias a PN junction of a junction diode. The PN junction has a junction capacitance. The method includes providing a reverse bias voltage change across the PN junction and detecting a value of the junction capacitance in response to the reverse bias voltage change. The value of the junction capacitance is a function of a temperature of the PN junction. An output signal is generated based on the detected junction capacitance, where the output signal indicates a temperature of an environment containing the junction diode.