LCD Controller Loop Control for Power Conservation
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Solution Overview
Problem
The existing LCD controller designs require a large number of I/O pins for capacitive switch sensing circuitries and LCD driver controllers, leading to increased chip size and complexity, and there is a need for power conservation methods, especially in scenarios where continuous displays are maintained for long periods.
Innovation Solution
The proposed LCD controller incorporates a charge pump for generating charge voltage, an oscillator for clock signal generation, and a loop control circuit that monitors LCD driver voltages to enable and disable the oscillator, allowing for power conservation by reducing the operation of the charge pump when the voltage is within a desired range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated LCD driver controller circuitry and capacitive sensing circuitry are used, then the controller can maintain continuous display functionality, but the chip size increases due to the large number of I/O pins required
Solution Approach 1:
The patent combines the LCD driver controller and capacitive sensing circuitry into a single integrated controller unit. The controller includes both LCD driver circuitry for driving display segments and capacitive sensing circuitry for detecting switch activations, eliminating the need for separate dedicated circuitries and reducing the overall chip size while maintaining continuous display functionality
Solution Approach 2:
The integrated controller performs multiple functions: it drives LCD display segments, detects capacitive switch activations, and manages power consumption. By making the controller universal and multi-functional, the patent eliminates the need for separate dedicated circuitries for each function, thereby reducing the number of I/O pins required and decreasing chip size
2Reliability
If the charge pump operates continuously to maintain LCD voltage, then the display can be maintained without changes, but power consumption increases
Solution Approach 1:
The charge pump operates periodically rather than continuously. The controller monitors the LCD voltage and activates the charge pump only when the voltage falls outside a predetermined range, allowing the display to be maintained without continuous operation and thereby reducing power consumption while ensuring display continuity
Solution Approach 2:
The controller includes feedback circuitry that continuously monitors the LCD voltage generated by the charge pump. Based on this feedback, the controller adjusts the charge pump operation by enabling it when voltage is outside the acceptable range and disabling it when voltage is within the range, optimizing power consumption while maintaining reliable display operation
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 enables efficient power management by minimizing the operation of the charge pump when the LCD voltage is within the desired range, thereby reducing power consumption and maintaining continuous displays while conserving energy.
Implementation Method 1
a charge pump for generating a charge voltage responsive to an external voltage and a clock signal
Data Source
AI summary
An LCD controller includes a charge pump for generating a charge voltage responsive to an external voltage and a clock signal. The controller further includes an oscillator for generating the clock signal responsive to an oscillator control signal. An LCD driver voltage circuit generates a plurality of LCD driver voltages for driving segments of an associated LCD display. A loop control circuit within the LCD controller monitors an LCD driver voltage from the LCD driver voltage circuit and generates the oscillator control signal responsive thereto to enable and disable the oscillator.