Sync Signal Acquisition Device with Forced Clamping Mode
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Solution Overview
Problem
Conventional sync signal acquisition devices in display systems suffer from DC level drift due to process and temperature changes, affecting the stability of sync signals and resulting in inconsistent display performance.
Innovation Solution
The implementation of a sync signal acquisition device comprising a transistor, resistor, clamper, analog multiplexer, and comparator, which switches between automatic and forced clamping modes to control the DC voltage level, preventing drift by allowing user-set output voltage in the forced clamping mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If automatic clamping mode is used to simplify the circuit structure, then device complexity is reduced, but DC voltage level stability deteriorates due to process and temperature changes
Solution Approach 1:
The patent implements a dynamic switching mechanism between automatic clamping mode and forced clamping mode through a mode selecting signal. The analog multiplexer dynamically connects different circuit configurations based on operating conditions, allowing the system to adapt from a simple automatic clamping structure to a forced clamping structure with stable DC voltage level when needed.
Solution Approach 2:
The patent changes the operating parameter by introducing a mode selecting signal that switches between two clamping modes. In automatic clamping mode, the DC voltage level is automatically adjusted but is unstable. In forced clamping mode, the DC voltage level is fixed by external voltage sources, providing stability. This parameter change resolves the contradiction between simplicity and stability.
2Reliability
If forced clamping mode is used to stabilize DC voltage level, then DC voltage level stability is improved, but device complexity increases due to additional switching components
Solution Approach 1:
The analog multiplexer serves multiple functions: it switches between automatic clamping mode and forced clamping mode, and also selects between different input signals (SOG or SOY). This multi-functionality reduces the need for separate dedicated circuits for each function, thereby limiting the increase in device complexity while achieving stable DC voltage level.
Solution Approach 2:
The patent uses a dynamic switching approach where the same analog multiplexer component handles both mode selection and signal selection. By making the switching mechanism dynamic and multi-functional, the patent minimizes the additional complexity introduced by the forced clamping mode compared to having completely separate circuits.
3Ease of operation
If automatic clamping mode is used at start-up, then ease of operation is improved, but measurement precision deteriorates due to DC level drift at higher temperatures
Solution Approach 1:
The patent performs preliminary action by using automatic clamping mode during start-up operation when the system is first initialized. This ensures easy operation and proper initialization. After warm-up, when temperature stability is achieved, the system switches to forced clamping mode to ensure measurement precision. This temporal separation of modes resolves the contradiction.
Solution Approach 2:
The patent dynamically adapts the clamping mode based on the operational phase. During start-up, automatic clamping mode provides ease of operation. After temperature stabilization, the system transitions to forced clamping mode to ensure precise sync signal measurement. This dynamic adaptation allows the system to optimize for different operational requirements at different times.
Data Source
AI summary
A sync signal acquisition device is disclosed which comprises a transistor, a resistor, a clamper, an analog multiplexer and a comparator. While operating in a composite HS mode, prior to the generation of the sync signal HS, the invention uses a conventional circuit to extract a composite sync signal at start-up, thereby allowing related circuits to generate the sync signal HS and a clamping signal. Then, a mode selecting signal is used to disable the automatic clamping mode and switch the analog multiplexer to a forced clamping mode. At this point, the output voltage of the damper is set by a user instead of process; accordingly, the DC voltage level is more controllable, but not subject to drift due to process changes or temperature changes.