Voltage Detector With Dual Resistive Ladders
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Solution Overview
Problem
Voltage detectors with a single resistive ladder experience increased leakage current at certain threshold levels, leading to accuracy issues, especially at low voltage thresholds and as temperature increases, which affects their performance in requiring high accuracy applications.
Innovation Solution
A multiple resistive ladder voltage detector configuration is employed, featuring two resistive ladders with transistors configured to tap intermediate nodes, where one ladder is selected to set a threshold voltage, and the other ladder is used to reduce leakage current by isolating the input node of the last transistor from ground, thereby improving accuracy across a wide range of threshold voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single resistive ladder is used in the voltage detector, then the device complexity is reduced, but the measurement precision deteriorates due to increased leakage current at certain threshold levels
Solution Approach 1:
The voltage detector is divided into multiple independent resistive ladders (first resistive ladder and second resistive ladder), each handling different voltage threshold ranges. This segmentation allows the system to optimize for low leakage current in specific ranges while maintaining overall functionality across a wide voltage spectrum.
Solution Approach 2:
The patent transitions from a single-dimension (one resistive ladder) approach to a multi-dimensional approach by introducing multiple resistive ladders with different configurations. Each ladder operates in a specific dimension of the voltage range, allowing the system to achieve high precision across the entire voltage spectrum by selecting the appropriate ladder for each measurement.
2Adaptability or versatility
If the voltage threshold is reduced to detect low voltages, then the adaptability is improved, but the leakage current increases leading to accuracy degradation
Solution Approach 1:
The voltage detection range is segmented into different segments handled by different resistive ladders. The first resistive ladder handles higher voltage thresholds while the second resistive ladder handles lower voltage thresholds with optimized transistor configurations that minimize leakage current in each respective range.
Solution Approach 2:
Different regions of the voltage range are assigned different quality characteristics through the use of multiple resistive ladders. Each ladder is optimized with specific transistor configurations and resistor ratios tailored to its designated voltage range, ensuring low leakage current and high accuracy for local voltage detection requirements.
3Temperature
If temperature increases, then the operational environment is expanded, but the leakage current increases reducing measurement precision
Solution Approach 1:
The circuit design anticipates temperature-induced leakage current increases by incorporating multiple resistive ladders with optimized transistor configurations before the problem manifests. The selected ladder for the current voltage range is pre-configured to minimize leakage current effects, providing a buffer against temperature-related precision degradation.
Solution Approach 2:
The patent changes critical parameters (resistor ratios, transistor threshold voltages, ladder configurations) based on the operating conditions and voltage range being measured. By selecting the appropriate resistive ladder and adjusting its parameters, the system compensates for temperature effects and maintains measurement precision across varying thermal environments.
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 effectively curtails leakage current, enhancing the accuracy of voltage detection, particularly at low threshold voltages and high temperatures, allowing for a larger range of voltage detection from 0.5 V to 100 V with reduced sensitivity to temperature variations.
Implementation Method 1
a first resistive ladder that includes a first string of resistors coupled between a sensing input node and a first node of the ladder selector... An input node of each transistor in the first set of transistors is coupled to a respective intermediate node between two resistors in a subset of resistors in the first string of resistors
Implementation Method 2
A selected transistor in one of the first set of transistors or the second set of transistors is turned on, and non-selected transistors of the first set of transistors and the second set of transistors are turned off to set a threshold voltage for a sensing output node
Data Source
AI summary
A device for monitoring voltage in a battery-operated system, the device including: a ladder selector configured to select between a first resistive ladder and a second resistive ladder; the first resistive ladder includes: a first string of resistors coupled between a sensing input node and a first node of the ladder selector; and a first set of transistors configured to tap intermediate nodes of a set of resistors in the first string of resistors; the second resistive ladder includes: a second string of resistors coupled between the sensing input node and a second node of the ladder selector; and a second set of transistors configured to tap intermediate nodes of a set of resistors in the second string of resistors; and wherein a selected transistor in one of the first set of transistors or the second set of transistors is turned on, and non-selected transistors of the first set of transistors and the second set of transistors are turned off to set a threshold voltage for a sensing output node.