Display Power Supply Circuit for Square-Wave AC Detection
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Solution Overview
Problem
Image display apparatuses fail to recognize and stabilize power supply when self-generated AC voltage is in the form of a square wave, leading to instability and potential failure to turn on.
Innovation Solution
Incorporating a power supply system with a first voltage detector using a resistor and a second voltage detector employing a differential circuit with a capacitor and resistor, along with a converter and controller, to differentiate between sine wave and square wave AC voltages and ensure stable operation by appropriately switching the converter's elements based on detected signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single voltage detector using a resistor is used, then the circuit configuration is simple, but it cannot recognize square wave AC voltage and the power cannot be turned on
Solution Approach 1:
The voltage detection function is segmented into two separate detection circuits: a first voltage detector using a resistor for sine wave detection, and a second voltage detector using a differential circuit with capacitor and resistor for square wave detection. Each detector is optimized for specific waveform types, enabling the system to handle multiple AC voltage forms without excessive complexity.
Solution Approach 2:
The power supply apparatus is designed with multi-functional voltage detection capability by incorporating both sine wave detection and square wave detection circuits. The controller selectively activates the appropriate detection circuit based on the input waveform type, making the system universally compatible with different AC voltage forms while maintaining operational stability.
2Adaptability or versatility
If the AC voltage waveform is not sine wave (e.g., square wave), then self-generated power can be supplied, but existing circuit configuration cannot recognize it causing power failure to turn on
Solution Approach 1:
The system dynamically adapts its detection mechanism based on the input AC voltage waveform. The controller monitors the input signal characteristics and dynamically switches between the first voltage detector (for sine waves) and the second voltage detector (for square waves), ensuring reliable operation across different waveform types while maintaining power on stability.
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
Enables stable operation of the image display apparatus even when square wave AC voltage is applied, ensuring consistent power supply and reducing power consumption by optimizing switching modes.
Implementation Method 1
a second voltage detector configured to detect the input AC voltage by using a differential circuit including a capacitor and a second resistor
Data Source
AI summary
An image display device of the present invention comprises a display and a power supply unit, and the power supply unit comprises: a first voltage detection unit that detects an input AC voltage by using a first resistance element; a second voltage detection unit that detects an input AC voltage by using a differential circuit having a capacitor element and a second resistance element; a converter that converts the level of the input voltage on the basis of a switching operation of a switching element so as to output a DC voltage; and a control unit that may control the switching element in the converter to be turned on, on the basis of a first signal detected by the first voltage detection unit or a second signal detected by the second voltage detection unit. As such, the present invention operates stably even when an AC voltage of a square wave is applied.