Reference Voltage Circuit Temperature Drift Compensation
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Solution Overview
Problem
Conventional semiconductor devices face challenges in generating reference voltages with high precision, as they are susceptible to variations in input voltage and temperature, leading to inadequate stability and accuracy.
Innovation Solution
The proposed solution involves a reference voltage generation circuit that incorporates multiple reference voltage sources with distinct temperature responses, a comparator system to select the appropriate voltage, and a resistor and diode configuration that includes polyresistors and diffusion resistors to achieve a flat temperature response, along with a regulator that uses switch arrays and decoders to adjust output voltages, ensuring stability and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single reference voltage source is used, then the circuit is simple, but the output precision and stability are insufficient due to susceptibility to voltage and temperature variations
Solution Approach 1:
The reference voltage generation circuit is divided into multiple independent reference voltage sources (first reference voltage source and second reference voltage source), each with different temperature responses. This segmentation allows the system to select the most appropriate reference voltage based on temperature conditions, thereby improving output precision while managing circuit complexity through modular design.
Solution Approach 2:
The circuit dynamically selects between different reference voltage sources based on temperature conditions through the comparator and selector mechanism. This dynamic adaptation allows the system to optimize its performance for different operating conditions, improving measurement precision without requiring a completely different circuit design for each condition.
2Reliability
If conventional single resistor configuration is used, then the manufacturing is simple, but the temperature drift cannot be effectively compensated
Solution Approach 1:
The resistor configuration uses a composite structure combining polyresistor portions and diffusion resistor portions in specific ratios. This composite resistor design enables effective temperature drift compensation by leveraging the different temperature coefficients of the two resistor types, achieving high temperature stability while maintaining manufacturability through standard semiconductor fabrication processes.
Solution Approach 2:
The invention changes the resistance parameters by using multiple resistors with different temperature coefficients (polyresistor and diffusion resistor) in a configured arrangement. By adjusting the resistance ratios and selecting appropriate resistor types, the system achieves temperature compensation without requiring complex manufacturing processes.
3Reliability
If multiple reference voltage sources with different temperature responses are used, then temperature drift compensation is improved, but the device complexity increases
Solution Approach 1:
The comparator continuously monitors the temperatures and automatically selects the appropriate reference voltage source based on the current temperature condition. This feedback mechanism enables automatic temperature drift compensation without requiring complex control circuits or manual intervention, balancing improved reliability with manageable circuit complexity.
Solution Approach 2:
The comparator and selector act as intermediary components that manage the interaction between multiple reference voltage sources. These intermediaries simplify the overall circuit structure by providing a systematic method for selecting the appropriate reference voltage, reducing the complexity that would otherwise arise from directly managing multiple reference sources.
4Measurement precision
If high precision reference voltage generation is implemented, then the output accuracy is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The invention uses parameter changes in the resistor configuration, specifically employing polyresistors and diffusion resistors with known and controllable temperature coefficients. By designing the resistor network to rely on ratios rather than absolute values, and by selecting resistor types with predictable characteristics, the system achieves high output accuracy while reducing the stringency of manufacturing precision requirements.
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 configuration significantly reduces temperature drift in reference voltages, achieving precision levels of 1 ppm/°C or less, thereby enhancing the stability and accuracy of output voltages across varying conditions.
Implementation Method 1
a second reference voltage source that generates a second reference voltage having a temperature response different from that of the first reference voltage
Implementation Method 2
a first comparator that compares the first and second reference voltages with each other to generate a first comparison signal
Implementation Method 3
one of the first and second resistors is composed of a combination of a polyresistor portion and a diffusion resistor portion
Data Source
AI summary
As one example of the invention disclosed herein, a reference voltage generation circuit has: a first reference voltage source generating a first reference voltage; a second reference voltage source generating a second reference voltage having a temperature response different from that of the first reference voltage; a first comparator comparing the first and second reference voltages to generate a first comparison signal; and a selector selectively outputting one of the first and second reference voltages as a reference voltage according to the first comparison signal.