State-Based Undervoltage Hysteresis Circuit
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Solution Overview
Problem
Existing undervoltage detection systems often oscillate when entering and exiting undervoltage conditions, leading to unnecessary deactivation and reactivation of electrical devices, which can damage components and reduce system reliability, especially at low supply voltage levels.
Innovation Solution
Implementing state-based undervoltage hysteresis with multiple thresholds to adapt activation levels based on system states, using comparators to determine voltage levels and selectively enable or disable loads, thereby reducing oscillations and allowing operation at low supply voltages without increasing the minimum operating voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hysteresis is used to avoid excessive cycling into and out of undervoltage lockout, then the frequency of deactivation and reactivation is decreased, but the minimum turn on voltage of the system is undesirably raised
Solution Approach 1:
The patent implements dynamic hysteresis thresholds that adapt based on system state. When the system is in an undervoltage lockout state, a first (lower) threshold is used, and when in a normal operating state, a second (higher) threshold is used. This dynamic adjustment allows the system to maintain stability while operating at lower minimum voltages compared to fixed hysteresis approaches.
Solution Approach 2:
The patent changes the hysteresis threshold parameter based on the detected system state. The control circuit dynamically switches between different threshold values (first threshold when undervoltage, second threshold when normal) to optimize both system stability and minimum operating voltage requirements.
2Device complexity
If a single undervoltage threshold is used for all system components, then the detection circuit is simple, but different system components with different minimum voltage supply levels cannot be properly operated
Solution Approach 1:
The patent segments the voltage detection and control into multiple state-based thresholds. Instead of using a single threshold for all components, it divides the voltage response into different states (undervoltage lockout state and normal operating state) with different thresholds, allowing different components with different minimum voltage requirements to be properly supported.
Solution Approach 2:
The control circuit is designed to universally handle multiple system components with different voltage requirements by implementing state-based threshold adjustment. This multi-functional approach allows the same detection circuit to adapt to various component voltage needs through dynamic threshold selection rather than requiring separate detection circuits for each component.
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 state-based undervoltage hysteresis system effectively reduces oscillations in detection circuits, enabling reliable operation at low supply voltages without relying on charge pumps, thus preventing component damage and minimizing conducted emissions.
Implementation Method 1
A detection circuit is often used to monitor the supply voltage and disable functions if the voltage level of the power supply is less than a minimum required voltage or an undervoltage threshold
Implementation Method 2
The use of hysteresis may undesirably raise the minimum turn on voltage of a system. Different system components may have different minimum voltage supply levels.
Data Source
AI summary
A method of undervoltage detection includes detecting a voltage level for a power supply of a system, placing the system in an undervoltage state if the voltage level is below an undervoltage threshold, activating a load of the system at a first power level if the detected voltage level exceeds a first activation threshold and if the system resides in the undervoltage state, and activating the load at a second power level if the detected voltage level exceeds a second activation threshold.