Display Driver LDO Hard Park Switching for Pixel Voltage Stability
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Solution Overview
Problem
Existing display technologies face challenges in maintaining stable pixel voltages during rapid and potentially deleterious changes, leading to inefficiencies and potential damage to display circuits.
Innovation Solution
Incorporation of bias voltage generator replacement circuitry and reference voltage replacement circuitry with hardened components to provide stable replacement voltages, coupled with a multiplexer to switch between normal and hard park modes, ensuring efficient operation and protection of display driver circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If replacement bias voltage and replacement reference voltage are provided to the LDO during rapid changes, then stability of pixel voltage is improved, but device complexity increases due to additional circuitry
Solution Approach 1:
The bias voltage generator is segmented into two parallel paths: a normal operation path and a replacement path with hardened circuitry. The multiplexer segments the voltage supply by selecting between normal and replacement voltages based on operational conditions, allowing the system to switch between configurations without requiring a completely redesigned circuit.
Solution Approach 2:
The multiplexer acts as an intermediary component that mediates between the normal bias voltage generator and the replacement bias voltage generator. It selectively connects either the normal or replacement voltage path to the LDO based on detected conditions, enabling smooth transition between operational modes without direct conflict between circuit paths.
2Reliability
If hardened circuitry is used for replacement voltage generation, then reliability under rapid changes is improved, but manufacturing complexity increases
Solution Approach 1:
Hardened circuitry with enhanced stability characteristics is applied locally only to the replacement voltage generator path, rather than requiring all circuitry to be hardened. This allows the critical replacement path to have superior reliability characteristics while the normal operation path can use standard manufacturing processes.
Solution Approach 2:
The patent implements partial hardening by creating a dedicated replacement voltage path with enhanced stability features only when needed, rather than over-engineering the entire system. The multiplexer enables this partial action by activating the hardened replacement path only during specific conditions, reducing overall manufacturing complexity while maintaining reliability where critical.
3Object-affected harmful factors
If multiplexer is added to switch between normal and hard park modes, then protection against rapid changes is improved, but device complexity increases
Solution Approach 1:
The replacement voltage generator and multiplexer are prepared in advance as a protective mechanism. When rapid changes are detected in the normal bias voltage, the system can immediately switch to the pre-configured replacement voltage path, providing preliminary protection against harmful voltage fluctuations before they can damage the LDO or display panel.
Solution Approach 2:
The system implements feedback monitoring of the bias voltage generated by the normal voltage generator. When the monitored voltage exceeds predetermined thresholds indicating rapid changes, the feedback signal triggers the multiplexer to switch from the normal voltage path to the replacement voltage path, providing automatic protection without external intervention.
Data Source
AI summary
An electronic device may include a display panel and a display driver. The display panel may include multiple pixels each receiving a supply voltage and a respective data voltage to emit light. The display driver may include a low drop-out regulator (LDO) to provide the supply voltage to the pixels. The LDO may operate in a normal operation mode and a hard park mode. In the normal operation mode, the LDO may generate the supply voltage based on receiving a reference voltage and a bias voltage within a bias voltage range to operate in the normal operation mode. In the hard park mode, the LDO may become idle (e.g., shut-down mode) based on receiving a hard park mode voltages from dedicated replacement circuits. For example, including the dedicated reference voltage replacement circuit with the display driver may improve reliability and efficiency of the electronic device when de-energizing the LDO.