DC/DC Module for LCD Driving Circuit Simplifies Voltage Conversion
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Solution Overview
Problem
The existing DC/DC modules for LCD driving circuits are complex and costly, requiring boost and negative charge pump architectures, which are inefficient and have limited output capacity as panel size increases.
Innovation Solution
A DC/DC module comprising a buck-boost circuit, LDO circuit, BUCK circuit, and charge pump circuit, which eliminates the need for boost and negative charge pump architectures, using a buck-boost circuit to generate a gate off-state voltage of -9V, an LDO circuit to produce a lower limit output voltage of -3V, and a charge pump to generate a gate on-state voltage of 33V from a 12V input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If boost circuit and negative charge pump architecture are used, then voltage conversion is achieved, but circuit structure becomes complex and hardware cost increases
Solution Approach 1:
The patent combines the boost circuit and negative charge pump into a single integrated DC/DC module architecture. The module integrates multiple voltage conversion functions (positive voltage generation, negative voltage generation, and ground reference) into one unified structure, reducing the number of separate components and simplifying the overall circuit structure while maintaining voltage conversion capability.
Solution Approach 2:
The DC/DC module is designed to perform multiple functions simultaneously: it generates the upper limit voltage VAA, lower limit voltage VBB, and provides ground reference through a single integrated structure. This multi-functional design eliminates the need for separate boost and negative charge pump circuits, reducing hardware complexity while maintaining all necessary voltage conversion capabilities.
2Device complexity
If boost circuit and negative charge pump architecture are used, then voltage conversion is achieved, but hardware cost increases
Solution Approach 1:
The patent combines the boost circuit and negative charge pump into a single integrated DC/DC module architecture. The module integrates multiple voltage conversion functions (positive voltage generation, negative voltage generation, and ground reference) into one unified structure, reducing the number of separate components and simplifying the overall circuit structure while maintaining voltage conversion capability.
Solution Approach 2:
The DC/DC module is designed to perform multiple functions simultaneously: it generates the upper limit voltage VAA, lower limit voltage VBB, and provides ground reference through a single integrated structure. This multi-functional design eliminates the need for separate boost and negative charge pump circuits, reducing hardware complexity while maintaining all necessary voltage conversion capabilities.
3Power
If negative charge pump is used for gate off-state voltage, then voltage conversion is achieved, but output capacity is limited as panel size increases
Solution Approach 1:
The patent combines the boost circuit and negative charge pump into a single integrated DC/DC module architecture. The module integrates multiple voltage conversion functions (positive voltage generation, negative voltage generation, and ground reference) into one unified structure, reducing the number of separate components and simplifying the overall circuit structure while maintaining voltage conversion capability.
Solution Approach 2:
The patent changes the output voltage parameter of the gate off-state voltage from the conventional -6V to -9V. This parameter change allows the circuit to provide stronger output capacity and better driving capability for larger panel sizes, while the integrated DC/DC module architecture ensures this is achieved without proportionally increasing circuit complexity.
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 solution simplifies the circuit structure, reduces hardware costs, and enhances load capacity, enabling strong gate off-state voltage output while maintaining efficient voltage conversion.
Implementation Method 1
The inductor Lf is located at the input side, which is called boost inductor. The working principle of the boost circuit is shown in FIG. 2. Wherein, Q is a transistor, the driving voltage of which typically is pulse width modulation (PWM) signal
Implementation Method 2
The charge pump is also called as switched-capacitor voltage converter, which is a kind of the DC-DC (converter) stored the energy by a so-called 'flying' or 'pumping' capacitor (rather than the inductor or transformer)
Data Source
AI summary
A DC/DC module comprises a buck-boost circuit, which is used to convert the input voltage of the DC/DC module into a gate off-state voltage VGL; a LDO circuit, which is used to convert the input voltage of the buck-boost circuit into a lower limit output voltage VBB of a liquid crystal driver; a BUCK circuit, which is used to convert the input voltage of the DC/DC module into an operating voltage VDD of a specific IC; a charge pump circuit, which is used to convert the input voltage of the DC/DC module into a gate on-state voltage VGH; wherein, the input voltage of the DC/DC module is used directly as an upper limit output voltage VAA. The DC/DC module according to the present invention has simple circuit structure, low hardware cost, and high load capacity.