DC Voltage Conversion Circuit for LCD Voltage Drop Compensation
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Solution Overview
Problem
The increasing size of TFT-LCDs leads to larger current in DC voltage conversion circuits, resulting in significant wiring resistance and voltage drops, which fail to meet the voltage requirements of electrical components, especially when current is high, and exceed limits when current is low.
Innovation Solution
A DC voltage conversion circuit comprising a voltage dividing unit, a voltage conversion unit, a first subtractor, an adder, a second subtractor, and a pulse width modulation unit, which adjusts the duty ratio of the pulse signal to maintain consistent voltage output across varying currents, using a field effect transistor and diodes to ensure the voltage received by electrical components is consistent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the input voltage is set higher to compensate for wiring voltage drop under high current conditions, then the voltage received by electrical components can meet requirements, but when current is small, the voltage input to electrical components will be too large and exceed their voltage limit
Solution Approach 1:
The patent implements dynamic voltage adjustment by using a DC voltage conversion circuit that automatically adapts the output voltage based on the actual current conditions. The circuit transitions from a fixed high voltage setting to a dynamic voltage regulation system that responds to load variations, ensuring optimal voltage delivery across different operating conditions.
Solution Approach 2:
The patent employs feedback mechanisms through voltage detection circuits and control logic that monitor the actual voltage and current conditions, then adjust the DC-DC conversion parameters accordingly. This closed-loop control enables the system to compensate for wiring voltage drops under high current while preventing overvoltage under low current conditions.
2Reliability
If the wiring width is increased to reduce resistance, then voltage drop decreases, but the board width of the printed circuit board is limited
Solution Approach 1:
The patent introduces a DC voltage conversion circuit as an intermediary device that actively compensates for the inherent voltage drop in narrow wiring. Instead of relying solely on physical wiring modifications, the system uses electronic voltage regulation to overcome the limitations of constrained PCB routing space.
Solution Approach 2:
The patent changes the voltage parameter dynamically through DC-DC conversion, adjusting the output voltage based on the actual voltage drop experienced in the wiring. This allows the system to maintain stable component voltage despite the physical constraints of narrow PCB traces.
3Productivity
If the current in DC voltage conversion circuit is increased to support larger TFT-LCD sizes, then display performance improves, but the voltage drop on wiring becomes significant and fails to meet voltage requirements
Solution Approach 1:
The patent implements dynamic voltage compensation that scales with current demand. As the TFT-LCD size and current requirements increase, the DC voltage conversion circuit automatically adjusts its output to compensate for the proportionally increased voltage drop, maintaining reliable voltage delivery across different display sizes.
Solution Approach 2:
The patent applies preliminary voltage boosting through the DC-DC conversion circuit to counteract the anticipated voltage drop caused by high current. By pre-compensating for the expected voltage loss in the wiring, the system ensures that the actual voltage reaching the components remains within required specifications.
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 solution ensures consistent voltage delivery to electrical components across different currents, improving product quality by compensating for voltage drops and preventing overvoltage, thus enhancing the performance and reliability of the liquid crystal display device.
Implementation Method 1
a first inductor L10, a first diode D10... A source electrode of the first field effect transistor Q10 is electrically connected with a first terminal of the first inductor L10. A second terminal of the first inductor L10 outputs an output voltage Vout
Implementation Method 2
a first field effect transistor Q10... A gate electrode of the first field effect transistor Q10 is connected with an output terminal of the PWM IC 100′, a source electrode of the first field effect transistor Q10 is electrically connected with a first terminal of the first inductor L10
Implementation Method 3
a first diode D10... A cathode of the first diode D10 is electrically connected with the first terminal of the first inductor L10 and an anode of the first diode D10 is grounded
Data Source
AI summary
The present invention provides a DC voltage conversion circuit and a liquid crystal display device. The DC voltage conversion circuit comprises a voltage dividing unit, a voltage conversion unit, a first subtractor, an adder, a second subtractor, and a pulse width modulation unit. The pulse width modulation unit is used for correspondingly adjusting the duty ratio of the pulse signal outputted when a voltage outputted from the output terminal of the second subtractor is smaller than or greater than a preset voltage difference, and the output voltage and the feedback voltage are increased or decreased until the voltage outputted from the second subtractor output is equal to the preset voltage difference. So as to increase the output voltage when the output current of the DC voltage conversion circuit is increased, and reduce the output voltage when the output current is decreased, and can ensure that the voltage received by the connected electrical components is consistent and the quality of the product is improved.