LCD Gray Voltage Circuit With Op-Amp Capacitor Pre-Charging
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Solution Overview
Problem
The existing hybrid driving circuits for LCD devices require high driving current to charge capacitors, leading to increased power consumption, as they rely on operational amplifiers to charge capacitors without their involvement in the charging process.
Innovation Solution
A circuit and method that utilize an operational amplifier to pre-charge capacitors and selectively output gray level voltages, reducing the need for high current generation by the gray level voltage generator, thereby minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the existing hybrid driving circuit uses operational amplifiers to charge capacitors, then the gray level voltage generator can provide stable voltages, but the driving current required to charge capacitors increases significantly, leading to higher power consumption
Solution Approach 1:
The patent applies preliminary action by pre-charging capacitors during a dedicated pre-charge period before the actual switching operation. The operational amplifier charges the capacitors in advance, so that when switching occurs, the capacitors are already charged and no additional high current is needed during the critical switching phase. This separates the charging function from the switching function, reducing peak current requirements and overall power consumption while maintaining voltage stability.
2Speed
If the gray level voltage generator generates high current to charge capacitors rapidly, then the response speed of the circuit improves, but the power consumption increases
Solution Approach 1:
The patent implements periodic action by dividing the operating cycle into distinct periods: a pre-charge period where capacitors are charged, and a switching period where pre-charged capacitors are used. This periodic separation allows the operational amplifier to charge capacitors at optimal speed during the pre-charge period without sustaining high current continuously, thereby achieving fast response when needed while minimizing overall power consumption during the non-switching intervals.
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 allows for reduced power consumption in the gray level voltage generator by leveraging the operational amplifier's high current driving capability to rapidly charge capacitors, addressing the inefficiencies of the existing circuits.
Implementation Method 1
an intermediate gray level voltage generator for receiving a first gray level voltage and a second gray level voltage among the plurality of gray level voltages and for selectively outputting one of the first gray level voltage and a third gray level voltage through a plurality of capacitors
Data Source
AI summary
A circuit for driving a liquid crystal display device, as embodied, includes: a gray level voltage generator for generating a plurality of gray level voltages; and an intermediate gray level voltage generator for receiving a first gray level voltage and a second gray level voltage among the plurality of gray level voltages and for selectively outputting one of the first gray level voltage and a third gray level voltage through a plurality of capacitors, a value of the third gray level voltage being between the first and second gray level voltage and set by the plurality of capacitors, the intermediate gray level voltage generator including: an operational amplifier for pre-charging the plurality of capacitors using a current outputted from the operational amplifier and for selectively outputting one of the first gray level voltage and the third gray level voltage.