On-Panel Charge Pump Voltage Control via Sampling Feedback
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Solution Overview
Problem
Existing display devices with charge pump booster circuits on glass substrates cannot monitor or control output voltage effectively, especially when it exceeds the withstand voltage of the LSI, leading to inefficiencies in power supply management and increased costs due to external LSI integration.
Innovation Solution
Incorporating a booster circuit with switches and a sampler on the display panel to monitor and control the output voltage by sampling internal voltages and adjusting input voltages and clock signals, allowing for precise voltage management within the panel without exceeding LSI withstand limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a charge pump booster circuit is integrated on the display panel substrate, then device complexity and cost are reduced, but the output voltage cannot be effectively monitored or controlled when it exceeds LSI withstand voltage
Solution Approach 1:
The patent introduces a sampler circuit as an intermediary component between the charge pump booster circuit and the monitoring system. The sampler captures and holds the output voltage signal at specific timing, converting the high-voltage monitoring problem into a low-voltage sampling problem that can be safely processed by standard LSI circuits. This mediator enables voltage monitoring without direct exposure to exceeding LSI withstand limits.
Solution Approach 2:
The patent implements a feedback control mechanism where the monitored output voltage signal is fed back to the control circuit. The control circuit adjusts the operating parameters of the charge pump booster circuit based on the feedback signal, enabling precise control of the output voltage. This closed-loop feedback system resolves the contradiction by enabling both integration and precise voltage control/monitoring.
2Measurement precision
If external LSI is used for power supply control, then voltage monitoring precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent merges the power supply control functions (charge pump booster, sampler, and control circuit) directly onto the display panel substrate. By integrating these previously separate external LSI components into a unified on-panel circuit system, the patent achieves both cost reduction and maintained monitoring precision through the synergistic combination of components.
Solution Approach 2:
The control circuit integrated on the substrate serves multiple functions: it controls the charge pump booster circuit operation, processes the sampled voltage signals, and implements feedback regulation. This multi-functional integration eliminates the need for separate external LSI components, reducing manufacturing cost while maintaining voltage monitoring precision through the versatile control circuit design.
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 improves voltage precision, reduces power consumption, and integrates power supply functions within the panel, lowering costs and enhancing picture quality by enabling precise control of drive voltages.
Implementation Method 1
a sampler for sampling a voltage signal at a first terminal of the pumping capacitance during a time period determined by a fifth input signal
Implementation Method 2
the charge pump booster circuit includes stabilizing capacitance for stabilizing output potential, pumping capacitance for storing charge on the stabilizing capacitance
Implementation Method 3
a plurality of switching elements for controlling the stabilizing capacitance and the pumping capacitance
Data Source
AI summary
A display device includes first and second voltage generation circuits each including a voltage circuit for outputting an internal voltage on the basis of a plurality of clocks, a sampling circuit for sampling an output signal from the voltage circuit, a monitoring circuit for comparing an output signal from the first sampling circuit with a predetermined voltage range and outputting a result, and a power supply generation circuit for generating a power supply voltage to be input to the voltage circuit on the basis of an output signal supplied from the monitoring circuit. The voltage circuit in the first voltage generation circuit is controlled on the basis of a level of the power supply voltage, and the voltage circuit in the second voltage generation circuit is controlled on the basis of periods of the clocks.