Reference Voltage Generation Circuit with Variable Resistors
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Solution Overview
Problem
Existing reference voltage generation circuits face limitations in flexibility and practicality across varying temperature conditions, as they either fail to adapt to temperature changes or suffer from leakage current issues at high temperatures, making them impractical for use in diverse operating environments.
Innovation Solution
A reference voltage generation circuit that incorporates a comparator with a PVT insensitive reference, a first resistor, and two variable resistors in parallel, along with a high transconductance transistor, allowing the output voltage to track temperature and process variations by adjusting the ratios of these components, enabling selective temperature dependency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PVT independent reference voltage generation circuit is used, then the output voltage remains constant across all conditions, but the circuit cannot adapt to temperature variations causing performance issues at low temperatures and leakage current at high temperatures
Solution Approach 1:
The patent introduces dynamic elements (variable resistors R2 and R3, and transistor T1) into the reference voltage generation circuit, allowing the resistance ratios to be adjusted based on temperature conditions. This enables the circuit to transition from a static PVT-independent configuration to a dynamic configuration that adapts to temperature variations, resolving the contradiction between reliability and temperature adaptability.
Solution Approach 2:
The patent changes the resistance parameters of the variable resistors R2 and R3, and utilizes the transconductance parameter of transistor T1, to create temperature-dependent reference voltages. By adjusting these parameters, the circuit can achieve different temperature dependencies (from independent to highly dependent) while maintaining reliable operation across temperature ranges.
2Manufacturing precision
If the circuit is designed to be PVT independent, then manufacturing precision is improved, but the circuit lacks flexibility for different operating environments
Solution Approach 1:
The patent creates a universal reference voltage generation circuit that can serve multiple functions: generating PVT-independent reference voltages when R2 and R3 are fixed, and generating temperature-dependent reference voltages when these resistors are variable. The transistor T1 further extends this universality by enabling temperature tracking through its transconductance characteristics, allowing a single circuit design to adapt to different operating environments.
3Adaptability or versatility
If variable resistors and transistor are added to enable temperature tracking, then device complexity increases, but temperature adaptability is improved
Solution Approach 1:
The patent uses variable resistors R2 and R3 as intermediary elements between the PVT-independent reference and the output, allowing controlled temperature dependency without directly modifying the core reference generation mechanism. The transistor T1 acts as another intermediary that provides temperature tracking through its transconductance, enabling temperature adaptability while keeping the base reference generation simple and manageable in complexity.
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 provides a reference voltage that can be temperature independent, temperature dependent, or highly dependent, offering greater flexibility and adaptability across different operating conditions, ensuring the circuit can function effectively in a wide range of environments.
Implementation Method 1
a high transconductance transistor, allowing the output voltage to track temperature and process variations
Data Source
AI summary
A reference voltage generation circuit for generating a reference voltage that can adaptively depend on temperature and process includes: a comparator, having a process, temperature and voltage (PVT) insensitive reference as a first input, and a feedback of the output as a second input, for generating a voltage reference output; a first resistor, coupled to the output of the operational amplifier; a second and a third variable resistor coupled in parallel, and coupled between the first resistor and ground; and a transistor, coupled between the third variable resistor and ground.