Undervoltage Lockout Circuit Power Consumption Reduction
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Solution Overview
Problem
Conventional under-voltage lockout circuits increase power consumption and circuit size due to static current generation and the need for external shut-down signal conversion in high-voltage power supply applications.
Innovation Solution
An under-voltage lockout circuit design that compares the driving voltage with two reference voltages, controlling the operation of a second under-voltage lockout circuit to minimize power consumption and circuit size, using a first reference voltage source and a comparison means with transistors and current mirrors to manage current flow and generate an under-voltage lockout signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional under-voltage lockout circuit compares driving voltage with a reference voltage to determine under-voltage condition, then the under-voltage protection function is achieved, but static current is generated increasing power consumption
Solution Approach 1:
The under-voltage lockout circuit is divided into two separate circuits: a first under-voltage lockout circuit that operates continuously with limited power consumption to generate control signals, and a second under-voltage lockout circuit that is activated only when needed. This segmentation allows the system to maintain protection functionality while reducing overall power consumption by keeping one circuit in a low-power state during normal operation.
2Use of energy by moving object
If an external shut-down signal is supplied to stop the under-voltage lockout circuit operation, then power consumption is reduced, but the shut-down signal must be converted to appropriate voltage range causing additional power consumption and increased circuit size
Solution Approach 1:
The first under-voltage lockout circuit automatically generates the control signal based on the driving voltage level without requiring external intervention or signal conversion. The circuit self-regulates by comparing the driving voltage with the reference voltage and producing the appropriate control output, eliminating the need for external shut-down signal conversion circuits and associated power consumption.
3Speed
If the first under-voltage lockout circuit operates continuously to provide control signal, then the protection response is immediate, but power consumption increases
Solution Approach 1:
The circuit operates dynamically by switching between two modes: the first under-voltage lockout circuit operates continuously in a low-power mode to maintain readiness, while the second circuit is activated dynamically when under-voltage conditions are detected. This dynamic operation allows the system to respond quickly to faults while minimizing power consumption during normal 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
Reduces power consumption of the under-voltage lockout circuit while minimizing the increase in size of the switch control circuit and power supply, by limiting power consumption to a first current that generates the first reference voltage and utilizing a zener diode for reference voltage determination.
Implementation Method 1
a second transistor configured to control a current flowing to the first transistor by mirroring the first current
Implementation Method 2
utilizing a zener diode for reference voltage determination
Implementation Method 3
a comparison means configured to output a result of comparison between the first reference voltage and the driving voltage
Data Source
AI summary
Exemplary embodiments of the present invention relate to an under-voltage lockout circuit, and a switching control circuit and a power supply including the same. The under-voltage lockout circuit according to an embodiment of the invention includes a first under-voltage lockout circuit comparing a driving voltage with a first reference voltage and a second under-voltage lockout circuit generating an under-voltage lockout signal based on a result of the comparison between the driving voltage and the second reference voltage. The first under-voltage lockout circuit stops operation of the second under-voltage lockout circuit when the driving voltage is lower than the first reference voltage and operates the second under-voltage lockout circuit when the driving voltage is higher than the first reference voltage. Power consumption of the first under-voltage lockout circuit is limited by a first current that generates the first reference voltage.