Current-Based Overvoltage and Undervoltage Detector Circuit
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Solution Overview
Problem
Conventional circuits for measuring overvoltage and undervoltage in lithium ion cells require high voltage elements and multiple bandgap circuits, leading to increased production costs and area consumption.
Innovation Solution
A circuit comprising voltage-to-current converters, current detectors, and bandgap circuits that convert voltage to current and compare it to reference currents to detect overvoltage and undervoltage, using a single bandgap circuit for each detection type and low voltage components, reducing area consumption and improving accuracy across a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct voltage measurement is used to detect overvoltage and undervoltage, then measurement capability is achieved, but high voltage elements and multiple bandgap circuits are required increasing area and cost
Solution Approach 1:
The patent replaces direct voltage measurement with current-based detection. Voltage-to-current converters transform voltage signals into current signals, which are then processed by current detectors and compared against reference currents generated by bandgap circuits. This substitution eliminates the need for high voltage elements and multiple bandgap circuits, reducing circuit area while maintaining detection capability.
Solution Approach 2:
The patent introduces voltage-to-current converters as intermediary components between the voltage measurement point and the detection circuitry. These converters act as mediators that transform voltage signals into current signals, enabling the use of low voltage components and reducing the overall circuit area required for overvoltage and undervoltage detection.
2Measurement precision
If multiple bandgap circuits are used for overvoltage and undervoltage detection, then detection accuracy is improved, but production costs and area consumption increase
Solution Approach 1:
The patent merges the overvoltage and undervoltage detection functions into a single integrated circuit structure. By using voltage-to-current converters to transform voltage signals into current signals, the circuit can share common components including bandgap circuits that generate reference currents. This merging reduces the total number of separate bandgap circuits needed while maintaining accurate detection for both overvoltage and undervoltage conditions.
3Measurement precision
If high voltage elements are used in the circuit, then voltage measurement capability is achieved, but area consumption and production costs increase
Solution Approach 1:
The patent substitutes high voltage elements with low voltage components by using voltage-to-current converters. These converters transform voltage signals into proportional current signals, allowing the rest of the circuit to operate at low voltages. This substitution maintains voltage measurement capability while eliminating the need for high voltage elements, thereby reducing circuit complexity and area consumption.
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 enables efficient detection of overvoltage and undervoltage conditions in lithium ion cells using low voltage components, reducing production costs and improving accuracy, while allowing for the reuse of current and reduced power consumption.
Implementation Method 1
each voltage-to-current converter receives an input voltage and generates an output current having a magnitude that is substantially proportional to the input voltage
Implementation Method 2
the first current detector determines which output current from the plurality of voltage-to-current converters is the largest current
Implementation Method 3
the overvoltage detector compares the largest current to an overvoltage reference current, wherein the overvoltage detector generates an overvoltage signal indicating whether the largest current is greater than the overvoltage reference current
Implementation Method 4
the undervoltage detector compares the smallest current to an undervoltage reference current, wherein the undervoltage detector generates an undervoltage signal indicating whether the smallest current is less than the undervoltage reference current
Implementation Method 5
the levels for overvoltage are set by bandgap circuits 102-0 to 102-2, and the levels for undervoltage are set by bandgap circuits 104-0 to 104-2
Data Source
AI summary
With batteries or cells, particularly lithium ion cells, it is important to determine when one or more cells have entered a fault condition (i.e., overvoltage or undervoltage). Conventional circuits employ measuring circuits that use multiple bandgap circuits and high voltage components. These conventional circuits, however, consume a great deal of area because of the use of these multiple bandgap circuits and the high voltage components. Here, a circuit is provided that reduces the number of bandgap circuits and reduces the number of high voltage components, reducing the area consumed and reducing the overall cost of production compared to conventional circuits.