Oscillation Abnormality Detection Circuit for LCD Driver Burn-In Prevention
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Solution Overview
Problem
Conventional semiconductor devices using external oscillation signals are prone to burn-in due to constant voltage application when the external oscillation signal experiences abnormalities such as pulse stoppage, which is not effectively detected and addressed.
Innovation Solution
Incorporation of an abnormality detection circuit within the liquid crystal display driver IC that monitors the external oscillation signal for abnormalities like pulse stoppage, using a logic inversion detection portion, clock monitor counter, and abnormality detection portion to generate an error signal, preventing burn-in by detecting and potentially stopping the display apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an external oscillation signal is used to generate internal clock signals, then power consumption is reduced and timing precision is improved, but the device becomes vulnerable to burn-in when the external signal experiences abnormalities such as pulse stoppage
Solution Approach 1:
The patent applies preliminary action by implementing an abnormality detection circuit that proactively monitors the external oscillation signal before burn-in can occur. The detection circuit continuously checks for pulse stoppage and other abnormalities, enabling the system to take preventive measures (such as switching to internal oscillation or notifying the host device) before damage occurs to the liquid crystal display panel.
2Device complexity
If constant voltage is applied during external oscillation signal abnormalities, then the device structure remains simple, but burn-in occurs on the liquid crystal display panel
Solution Approach 1:
The patent uses an intermediary approach by introducing an abnormality detection circuit as a mediator between the external oscillation signal input and the liquid crystal display panel. This detection circuit acts as a protective intermediary that monitors signal health and can trigger protective actions (such as switching oscillation sources or generating error signals) to prevent burn-in without requiring complete redesign of the entire system.
3Device complexity
If no abnormality detection is implemented, then device complexity is low, but external oscillation signal abnormalities go undetected and cause burn-in
Solution Approach 1:
The patent applies self-service by implementing a self-monitoring capability within the semiconductor device. The abnormality detection circuit uses internal resources (the existing oscillation signal lines and logic circuits) to monitor itself and the external signal, generating error signals when abnormalities are detected. This self-service approach enables detection without requiring extensive external monitoring equipment.
Data Source
AI summary
A semiconductor device includes, for example, an external terminal configured to accept an external input of an external oscillation signal, an internal oscillation portion configured to generate an internal oscillation signal, a logic inversion detection portion configured to generate a reset signal upon detecting logic inversion of a first internal signal corresponding to the external oscillation signal, a monitor counter configured to increase or decrease a count output value in accordance with the internal oscillation signal and to reset the count output value in accordance with the reset signal, and an abnormality detection portion configured to detect, in accordance with the count output value, whether or not there is an abnormality in the external oscillation signal.