Electro-optical Device D/A Converter Noise Isolation
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Solution Overview
Problem
Existing electro-optical devices with D/A converter circuits are prone to noise interference, affecting the linearity of output voltage and display quality due to shared ground potential usage, and require additional terminals for power supply, increasing the semiconductor substrate area.
Innovation Solution
An electro-optical device with a driving circuit including a D/A converter circuit, a power supply circuit that generates multiple power supply potentials, and a selective coupling mechanism for power supply wiring lines to capacitance elements, allowing for improved noise resistance and reduced substrate area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the ground potential Gnd is used for the D/A converter circuit, then the circuit can share power supply resources, but noise interference increases and output characteristics deteriorate
Solution Approach 1:
The patent divides the power supply system into separate segments: the D/A converter circuit uses a dedicated power supply potential (VDD) distinct from the ground potential (Gnd) used by other circuits. This segmentation isolates the noise-sensitive D/A converter from ground noise, preventing noise coupling while maintaining power supply sharing benefits through the common VDD connection.
2Reliability
If a separate power supply terminal is added for the D/A converter circuit, then noise interference is reduced, but the semiconductor substrate area increases
Solution Approach 1:
The patent makes the existing power supply terminal (VDD terminal) serve multiple functions: it supplies power to both the D/A converter circuit and other circuits simultaneously. This multi-functionality eliminates the need for additional dedicated power supply terminals, maintaining noise resistance through separate potential supply while avoiding substrate area increase.
3Area of stationary object
If the D/A converter circuit uses common ground potential with other circuits, then the substrate area is minimized, but noise from other circuits affects the output linearity
Solution Approach 1:
The patent introduces a dedicated power supply potential (VDD) as an intermediary between the power supply source and the D/A converter circuit. This intermediary potential acts as a noise isolation barrier, separating the D/A converter from ground noise while maintaining electrical connection, thus preventing noise coupling without requiring physical isolation that would increase substrate area.
Data Source
AI summary
An electro-optical device includes: a data signal output circuit including a D/A converter circuit; a plurality of terminals; a control circuit supplied with a power supply potential VL from at least one terminal of the plurality of terminals via a first power supply wiring line; and a power supply circuit configured to generate a power supply potential VPL in accordance with potentials AVDD and AVSS supplied via two or more terminals of the plurality of terminals and supply the power supply potential VPL to a second power supply wiring line. The D/A converter circuit includes a plurality of capacitance elements. The first power supply wiring line or the second power supply wiring line is selectively coupled to one portion of the plurality of capacitance elements.