Power Supply Circuit Voltage Protection Mechanism
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Solution Overview
Problem
Power supply circuits are vulnerable to damage from abnormal AC voltages, which can exceed rated voltages due to incorrect connections or poor power quality, potentially damaging smoothing capacitors.
Innovation Solution
A power supply circuit with a rectifying circuit, smoothing capacitor, first switching element, comparison circuit, and driving circuit that sets the switching element to an ON state when the index voltage is lower than the reference voltage and to an OFF state when it exceeds the reference voltage, preventing excessive voltage application to the capacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a power supply circuit is connected to high voltage power supply or operates in area with poor power quality, then the power supply circuit can operate with higher voltage input, but the smoothing capacitor may be damaged due to abnormal voltage exceeding rated voltage
Solution Approach 1:
The comparison circuit performs preliminary detection of the rectified voltage before it reaches the capacitor. When the voltage exceeds the reference voltage threshold, the driving circuit proactively turns off the switching element before excessive voltage can be applied to the capacitor, preventing damage before it occurs.
Solution Approach 2:
The comparison circuit continuously monitors the rectified voltage and provides feedback to the driving circuit. This feedback mechanism enables real-time control of the switching element, adjusting its state based on the actual voltage conditions to protect the capacitor while allowing normal operation.
2Reliability
If a switching element is added with control circuits to protect the capacitor, then the capacitor is protected from abnormal voltage, but the device complexity increases
Solution Approach 1:
The invention changes the control parameter of the switching element from continuous operation to state-based operation (ON/OFF states controlled by voltage threshold comparison). This parameter change simplifies the control logic while providing effective protection, as the switching element only needs to respond to voltage threshold violations rather than complex control signals.
Solution Approach 2:
The comparison circuit acts as an intermediary between the rectifying circuit and the driving circuit. It mediates the voltage information and converts it into a control signal that the driving circuit can act upon, simplifying the overall control architecture by introducing a dedicated voltage monitoring 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
This configuration effectively suppresses the application of abnormal voltages to the capacitor, protecting it from damage and ensuring stable operation by controlling the switching element based on voltage comparisons, thereby reducing the risk of capacitor damage.
Implementation Method 1
a rectifying circuit configured to rectify the AC voltage
Implementation Method 2
a capacitor configured to smooth the rectified voltage
Data Source
AI summary
A power supply circuit is a power supply circuit that generates a direct current (DC) voltage from an alternating current (AC) voltage, and includes a rectifying circuit that rectifies the AC voltage, a capacitor that smooths the rectified voltage, a first switching element disposed on a path for charging the capacitor, a comparison circuit that compares an index voltage depending on the smoothed voltage with a reference voltage, and a driving circuit that sets the first switching element to an ON state, in a state in which the index voltage is lower than the reference voltage, and sets the first switching element to an OFF state, in a state in which the index voltage exceeds the reference voltage.