Under Voltage Lock Out Circuit Dynamic Threshold Switching
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Solution Overview
Problem
Conventional under voltage lock out (UVLO) circuits with hysteresis characteristics fail to accurately manage the start-up sequence when the battery voltage fluctuates between the first and second threshold voltage values, leading to potential malfunction of electronic circuits.
Innovation Solution
An under voltage lock out circuit that monitors the input voltage and adjusts the threshold voltage based on comparison signals and start-up signals, preventing the execution of the start-up sequence when the input voltage is below the required level, and switching between hysteresis and non-hysteresis states to ensure proper operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If hysteresis characteristic is provided to the threshold voltage, then the circuit can prevent oscillation during voltage transitions, but the circuit may execute start-up sequence inappropriately when voltage fluctuates between threshold values
Solution Approach 1:
The patent applies dynamics by making the threshold voltage switchable between two states: a first threshold voltage when the UVLO signal is low, and a second threshold voltage when the UVLO signal is high. This dynamic adjustment of the threshold voltage based on the UVLO signal state allows the circuit to adapt to different voltage conditions and prevent inappropriate start-up sequence execution during voltage fluctuations.
Solution Approach 2:
The patent implements feedback by using the UVLO signal, which is generated based on the comparison between the monitored voltage and the threshold voltage, to control the threshold voltage switching. This feedback mechanism ensures that the threshold voltage adjusts appropriately in response to voltage changes, maintaining stable operation while preventing oscillation and inappropriate start-up execution.
2Device complexity
If the threshold voltage is fixed, then the circuit operation is simple, but the circuit cannot adapt to voltage fluctuations and may malfunction
Solution Approach 1:
The patent applies dynamics by implementing a switchable threshold voltage that can change between a first threshold voltage and a second threshold voltage based on the UVLO signal state. This dynamic threshold adjustment allows the circuit to adapt to voltage fluctuations without requiring complex additional components, maintaining relatively simple circuit structure while improving reliability.
3Speed
If the start-up sequence is executed when voltage is between threshold values, then the circuit responds quickly to voltage changes, but the circuit may malfunction due to insufficient voltage
Solution Approach 1:
The patent applies dynamics by using two different threshold voltages depending on the UVLO signal state. When the UVLO signal is high (indicating sufficient voltage), the second threshold voltage is used, allowing quick start-up response. When the UVLO signal is low (indicating insufficient voltage), the first threshold voltage is used, preventing start-up execution and avoiding malfunction. This dynamic threshold selection achieves both fast response and reliable operation.
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 ensures that the start-up sequence is executed only when the input voltage is above the threshold, preventing malfunctions and ensuring reliable operation of electronic circuits even during voltage fluctuations.
Implementation Method 1
a voltage comparison unit which compares the input voltage and a predetermined threshold voltage, and outputs a comparison signal
Data Source
AI summary
An under voltage lock out circuit which monitors an input voltage and executes a predetermined sequence when the input voltage satisfies a predetermined condition may include a voltage comparison unit which compares the input voltage and a predetermined threshold voltage, and outputs a comparison signal; a logic circuit which receives the comparison signal output from the voltage comparison unit and a start-up signal instructing start-up of an equipment mounted with the under voltage lock out circuit, and asserts a sequence control signal when start-up is instructed by the start-up signal in a state the input voltage is higher than the threshold voltage; and a sequence circuit which executes a predetermined sequence when the sequence control signal is asserted, wherein the predetermined threshold voltage is switched according to the sequence control signal.