Power Supply Control Circuit for LCD Power Cutoff
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Solution Overview
Problem
Conventional liquid crystal displays continue to consume power after being turned off due to residual electrical coupling with the commercial power outlet, leading to inefficiencies and significant power waste, especially when in a long-term turned-off state.
Innovation Solution
A power supply control circuit with a controllable switch and control circuit that disconnects the power supply when the liquid crystal display is turned off, ensuring complete disconnection from the commercial power outlet and preventing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a power control key is used to turn off the liquid crystal display, then the display stops working and user convenience is improved, but the power supply line remains electrically coupled to the commercial power outlet causing continuous power consumption
Solution Approach 1:
The patent extracts the power supply control function from the existing power control key mechanism. By adding a separate controllable switch (electromagnetic switch or transistor) that can completely disconnect the power supply line from the commercial power outlet, the system separates the display control function from the power cutoff function, enabling complete power disconnection while maintaining ease of operation through the same power control key.
Solution Approach 2:
The patent introduces an electromagnetic switch or transistor as an intermediary component between the power supply line and the load circuit. This intermediary element is controlled by the control circuit to open or close the power supply path, acting as a mediator that enables complete power disconnection without affecting the user-friendly power control interface.
2Speed
If the power supply line remains connected to the commercial power outlet, then the liquid crystal display can be quickly turned on again, but interface circuits continue to consume power unnecessarily
Solution Approach 1:
The patent extracts the interface circuits from the always-powered state by introducing a controllable switch that can completely disconnect them from the power supply. The switch is controlled by the control circuit to open when the display is turned off, removing the interface circuits from the active electrical system and eliminating their power consumption while maintaining quick startup capability.
3Productivity
If a conventional power control key is used, then the control terminal can be pulled down to stop driving circuits and inverter circuit, but the power supply signal is not cut off completely
Solution Approach 1:
The patent extracts the power cutoff function from the incomplete control terminal pull-down mechanism. By implementing a controllable switch in series with the power supply line that can completely open the electrical path, the system achieves complete power cutoff reliability while maintaining the productivity benefit of efficient display turn-off through the same power control key.
Solution Approach 2:
The patent introduces a controllable switch as an intermediary element that provides complete power cutoff reliability. This switch acts as a mediator between the power supply line and the load circuit, ensuring that when activated by the control circuit in response to the power control key, it completely disconnects the power supply signal and achieves reliable power cutoff.
Data Source
AI summary
An exemplary power supply control circuit (200) includes a first port (201), a second port (202), a third port (203), a controllable switch (280), and a control circuit (270). The first and second ports are configured to receive a power supply voltage signal. The second and third ports are configured to output the power supply voltage signal to a load circuit. The controllable switch includes a control member (281) and a switch member (282). The control circuit is configured to control a working state of the control member. When the load circuit stops working, the control circuit controls the control member to control the switch member to be disconnected, so as to cut off the power supply voltage signal from outputting to the load circuit. A liquid crystal display (400) using the power supply control circuit is also provided.