Reference Voltage Circuit With Op-Amp-Free PTAT Compensation
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Solution Overview
Problem
Existing reference voltage generation circuits face accuracy issues due to stress and noise, particularly when using operational amplifiers, leading to variations and decreased precision.
Innovation Solution
A reference voltage generation circuit that generates a reference voltage by combining a constant current source, a Zener diode for constant voltage, a PTAT current generation circuit without operational amplifiers, and a temperature characteristic adjustment resistor, canceling temperature characteristics to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If operational amplifiers are used in the reference voltage generation circuit, then the circuit can generate stable reference voltage, but the noise and variations increase leading to decreased accuracy
Solution Approach 1:
The patent removes operational amplifiers from the reference voltage generation circuit, extracting the noise source while maintaining stability through alternative components (Zener diode and PTAT current source) that do not introduce the same level of noise and variation
Solution Approach 2:
The patent replaces expensive and noise-prone operational amplifiers with simpler, more robust components (Zener diode and PTAT current source) that provide equivalent or superior performance in terms of noise immunity and long-term stability
2Temperature
If temperature compensation is implemented using conventional methods, then temperature characteristics can be adjusted, but the circuit complexity increases
Solution Approach 1:
The patent combines the temperature compensation function directly into the reference voltage generation path by subtracting the PTAT voltage from the Zener voltage, eliminating the need for separate compensation circuits and reducing overall circuit complexity
Solution Approach 2:
The PTAT current source automatically generates a voltage that tracks temperature changes, providing self-compensation for temperature drift without requiring external control circuits or additional 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
The proposed circuit reduces temperature variations and noise, enhancing the accuracy of the reference voltage without the need for operational amplifiers, thereby improving overall precision.
Implementation Method 1
a constant voltage generation circuit having a Zener diode for generating a constant voltage based on a Zener voltage
Implementation Method 2
a current generation circuit for generating a PTAT current having a positive temperature characteristic with respect to absolute temperature without an operational amplifier
Implementation Method 3
a temperature characteristic adjustment circuit including a temperature characteristic adjustment resistor
Data Source
AI summary
A reference voltage generation circuit for outputting a reference voltage includes: a constant current source; a constant voltage generation circuit having a Zener diode for generating a constant voltage based on a Zener voltage; a current generation circuit for generating a PTAT current having a positive temperature characteristic with respect to absolute temperature without an operational amplifier; and a temperature characteristic adjustment circuit including a temperature characteristic adjustment resistor. A voltage acquired by subtracting a voltage drop in the temperature characteristic adjustment circuit when the PTAT current flows from the constant voltage is output as the reference voltage.