Voltage Threshold Sensing Using Zener Diode Current Mirror
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Solution Overview
Problem
Conventional voltage sensing systems using resistive dividers face issues with high variability in voltage threshold detection due to internal component variations and temperature effects, leading to increased current consumption and die size, and require complex circuit blocks and trimming for accuracy.
Innovation Solution
A voltage sensing system employing a high side current mirror coupled with a Zener diode and a resistor, which generates a comparison voltage for a comparator to determine if the input voltage is above or below a reference voltage, reducing quiescent current and eliminating the need for trimming, while maintaining accuracy across temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a resistive divider is used to compare voltage with a reference voltage, then voltage threshold detection is achieved, but high variability in detection accuracy occurs due to internal component variations and temperature effects
Solution Approach 1:
The patent introduces a Zener diode as an intermediary component between the voltage source and the comparator. The Zener diode generates a reference voltage that is less sensitive to temperature and process variations compared to traditional resistive dividers. This intermediary element stabilizes the voltage threshold detection by providing a more reliable reference voltage that compensates for environmental variations.
Solution Approach 2:
The patent changes the operating parameters of the voltage sensing system by using a Zener diode operated in its breakdown region, where it maintains a relatively constant voltage across a range of currents. This parameter change allows the system to achieve more stable voltage threshold detection across temperature and process variations, directly addressing the reliability issue.
2Measurement precision
If complex circuit blocks and trimming are used to improve voltage threshold detection accuracy, then measurement precision improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The Zener diode inherently provides its own voltage reference without requiring external trimming or complex calibration circuits. The diode's breakdown voltage is determined by its physical characteristics, which are relatively stable across temperature and process variations. This self-service approach eliminates the need for complex trimming mechanisms and reduces overall device complexity while maintaining high measurement precision.
3Measurement precision
If traditional voltage sensing circuits are used, then voltage threshold detection is achieved, but quiescent current consumption and die size increase
Solution Approach 1:
The patent extracts the voltage reference generation function from the complex resistive divider network and implements it using a simple Zener diode. This extraction simplifies the circuit topology, removing unnecessary components that contribute to quiescent current consumption and die size. The Zener diode provides the essential reference voltage function with minimal current requirements, directly addressing the energy consumption issue.
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 system achieves stable performance with reduced area and current consumption, providing accurate detection of voltage thresholds with lower variability across temperatures and processes, and eliminates the need for complex trimming, resulting in improved accuracy and efficiency.
Implementation Method 1
The at least one diode may be a Zener diode
Data Source
AI summary
Implementations of voltage sensing systems may include: a high side current mirror coupled to a reference current source coupled to at least one diode. The at least one diode may be coupled to a resistor and to a comparator. The resistor may be coupled to the ground. The comparator may be coupled with a reference voltage. The comparator may be configured to receive a comparison voltage from the diode and output whether the comparison voltage is higher or lower than the reference voltage.