Hybrid Reverse Bandgap Circuit With Configurable DTS Mode
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Solution Overview
Problem
Traditional bandgap reference (BGR) and digital temperature sensor (DTS) designs face challenges in achieving low power and low cost requirements, especially in portable devices, due to high power consumption, complex designs, and limited availability of certain semiconductor processes, which affect their accuracy and efficiency.
Innovation Solution
The low power hybrid reverse bandgap reference and digital temperature sensor (LPHR) utilizes subthreshold metal oxide semiconductor transistors and parasitic PNP BJTs to create a reverse bandgap voltage, allowing for configurable operation as either a BGR or DTS with a linear transfer function, using unbalanced amplifiers and scaled emitter-base voltages to achieve high accuracy and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional bandgap reference and digital temperature sensor designs are used, then accurate voltage reference and temperature sensing are achieved, but power consumption is high
Solution Approach 1:
The patent combines the bandgap reference circuit and digital temperature sensor into a single integrated circuit that shares common components including BJT devices, resistors, and amplifiers. This merging reduces overall power consumption while maintaining the accuracy of both functions through shared signal paths and common reference voltages.
Solution Approach 2:
The circuit is designed to perform multiple functions using the same hardware components. The bandgap reference circuit generates a stable reference voltage that is simultaneously used for voltage regulation and temperature sensing operations, making the system multi-functional and reducing the power required for separate circuits.
2Measurement precision
If traditional bandgap reference and digital temperature sensor designs are used, then accurate voltage reference and temperature sensing are achieved, but device complexity is high
Solution Approach 1:
The patent integrates the bandgap reference and temperature sensor functions into a single circuit block that shares transistors, resistors, and amplifiers. This consolidation reduces the number of discrete components and simplifies the overall design while preserving the measurement accuracy of both functions.
Solution Approach 2:
The same circuit components serve dual purposes: the bandgap reference circuit generates a stable voltage reference that is simultaneously utilized for both voltage regulation and temperature sensing operations, reducing design complexity through multi-functionality.
3Measurement precision
If traditional bandgap reference and digital temperature sensor designs are used, then temperature sensing is achieved, but conversion time is slow
Solution Approach 1:
The circuit maintains continuous operation of the bandgap reference and temperature sensing functions without requiring periodic re-initialization or sequential activation. The shared amplifiers and signal paths enable simultaneous and continuous temperature measurements, reducing conversion time while maintaining accuracy.
4Use of energy by moving object
If portable device requirements are implemented, then low power and low cost are achieved, but temperature independence and PSRR performance deteriorate
Solution Approach 1:
The circuit employs carefully selected transistor sizing ratios and resistor values to optimize the temperature coefficients of the bandgap reference. By adjusting these parameters, the circuit achieves temperature independence (zero temperature coefficient) while maintaining low power consumption suitable for portable devices.
Solution Approach 2:
The patent replaces traditional mechanical trimming methods with electrical compensation techniques using programmable resistors and digital control. This substitution maintains temperature independence and power supply rejection performance while reducing the physical size and power consumption required for portable applications.
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 LPHR achieves high accuracy across a wider temperature range, consumes less power, and provides faster conversion times compared to existing designs, with improved temperature independence and PSRR performance, while maintaining a linear code-to-temperature transfer function.
Implementation Method 1
The low power hybrid reverse bandgap reference and digital temperature sensor (LPHR) utilizes subthreshold metal oxide semiconductor transistors and parasitic PNP BJTs to create a reverse bandgap voltage
Data Source
AI summary
A low power hybrid reverse (LPHR) bandgap reference (BGR) and digital temperature sensor (DTS) or a digital thermometer, which utilizes subthreshold metal oxide semiconductor (MOS) transistor and the PNP parasitic Bi-polar Junction Transistor (BJT) device to form a reverse BGR that serves as the base for configurable BGR or DTS operating modes. The LPHR architecture uses low-cost MOS transistors and the standard parasitic PNP device. Based on a reverse bandgap voltage, the LPHR can work as a configurable BGR. By comparing the configurable BGR with the scaled base-emitter voltage, the circuit can also perform as a DTS with a linear transfer function with single-temperature trim for high accuracy.