Voltage Supervisor Threshold Circuit With Temperature-Stable Hysteresis
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Solution Overview
Problem
Conventional voltage supervisors face challenges in maintaining accurate and temperature-insensitive threshold voltages, especially when operating above the bandgap voltage, leading to potential device damage and functional failures due to temperature-dependent variations.
Innovation Solution
A scaling circuit is implemented using a combination of resistors and transistors to generate a temperature-insensitive threshold voltage, which up-scales the bandgap voltage and incorporates hysteresis to prevent oscillations, ensuring reliable detection regardless of temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional voltage supervisors operate above bandgap voltage, then they can provide higher supply voltages for electronic components, but temperature-dependent variations cause threshold voltage drift leading to inaccurate detection
Solution Approach 1:
The patent changes the operating parameters by using a bandgap reference voltage (typically 1.2V) as the threshold detection reference, which has a positive temperature coefficient that compensates for the negative temperature coefficient of the voltage supervisor's threshold. This parameter selection ensures that the threshold voltage remains stable across temperature variations, resolving the contradiction between operating above bandgap voltage and maintaining temperature-insensitive threshold detection.
2Device complexity
If simple threshold detection circuits are used, then device complexity is reduced, but temperature variations cause false triggering and functional failures
Solution Approach 1:
The patent introduces a bandgap reference circuit as an intermediary element that provides a temperature-stable reference voltage for threshold detection. This intermediary component mediates between the temperature variations and the threshold detection function, ensuring reliable operation without requiring complex temperature compensation circuits or multiple sensing elements.
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 solution provides a temperature-insensitive threshold voltage with minimal variation over a wide temperature range, preventing false triggering and ensuring accurate power management, thus protecting electronic devices from voltage-related damage.
Implementation Method 1
a comparator having an output. The output is coupled to the first gate terminal and the second gate terminal
Implementation Method 2
A scaling circuit is implemented using a combination of resistors and transistors to generate a temperature-insensitive threshold voltage
Implementation Method 3
A scaling circuit is implemented using a combination of resistors and transistors to generate a temperature-insensitive threshold voltage
Implementation Method 4
incorporates hysteresis to prevent oscillations, ensuring reliable detection regardless of temperature changes
Data Source
AI summary
Methods, apparatus, and systems are disclosed for voltage supervisors. An example apparatus includes a first switch having a first source, a first drain, and a first gate, a first resistor having a first terminal and a second terminal, the first terminal coupled to the first source and second terminal coupled to the first drain, a second resistor having a third terminal and a fourth terminal, the third terminal coupled to the second terminal, a third resistor having a fifth terminal and a sixth terminal, the fifth terminal coupled to the fourth terminal, a fourth resistor having a seventh terminal and an eighth terminal, the seventh terminal coupled to the sixth terminal, a second switch having a second source, a second drain, and a second gate, the second source coupled to the seventh terminal, and a comparator having an output, the output coupled to the first gate and the second gate.