Two-Stage Pass Transistor Circuit for Wide Grayscale Selection
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Solution Overview
Problem
Semiconductor devices face challenges in selecting and outputting grayscale signals with large output potential widths without increasing circuit area and inhibiting noise from selection circuits.
Innovation Solution
A semiconductor device comprising a first circuit with multiple pass transistors cascaded to a second circuit, utilizing a low-pass filter to reduce noise and efficiently handle large grayscale signals, including a digital-analog converter circuit and an analog-digital converter circuit to generate ramp signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional selection circuit is used to select grayscale signals with large output potential width, then the grayscale signal can be selected, but the circuit area increases significantly
Solution Approach 1:
The selection circuit is divided into multiple stages: a first selection circuit that selects based on major bit patterns and a second selection circuit that selects based on minor bit patterns. This segmentation allows the circuit to handle large grayscale signal ranges without requiring a single large-scale selection circuit, thereby reducing overall circuit area while maintaining full grayscale selection capability.
Solution Approach 2:
The second selection circuit is nested within the output path of the first selection circuit. The first selection circuit outputs to intermediate nodes that feed into the second selection circuit, creating a nested structure where the smaller second selection circuit refines the selection made by the larger first selection circuit. This nested arrangement optimizes space utilization and reduces total circuit area.
2Adaptability or versatility
If a selection circuit with large output potential width is used, then grayscale signals can be selected, but noise from the selection circuit increases
Solution Approach 1:
The selection process is segmented into two independent selection circuits operating at different stages. Each circuit handles a portion of the selection task, which distributes the noise generation across multiple smaller circuits rather than one large circuit. This segmentation reduces the noise impact on any single signal path.
Solution Approach 2:
The first selection circuit acts as an intermediary between the input grayscale signals and the second selection circuit. It pre-selects signals based on major bit patterns, reducing the burden on the second circuit and minimizing the noise generated during final selection. This intermediary stage allows for cleaner signal transitions.
3Area of stationary object
If the number of transistors in the selection circuit is reduced, then circuit area decreases, but the ability to handle large output potential width is compromised
Solution Approach 1:
The transistor usage is segmented between two selection circuits. The first selection circuit uses a set number of transistors to handle major bit pattern selection, while the second selection circuit uses fewer transistors to handle minor bit pattern selection. This segmentation allows the system to handle large output potential widths without requiring all transistors to be present in a single circuit, optimizing the total transistor count.
Solution Approach 2:
The selection process transitions from a single-dimension approach (one large selection circuit) to a multi-dimensional approach (two-stage selection with different transistor configurations). The first selection circuit operates on major bit patterns while the second operates on minor bit patterns, effectively adding a temporal and functional dimension to the selection process. This allows efficient handling of large potential widths with reduced transistor count.
Data Source
AI summary
A semiconductor device using a pass transistor is provided. The semiconductor device includes a first circuit, a second circuit, a plurality of input terminals, and an output terminal. The first circuit includes a plurality of first transistors functioning as pass transistors, and the second circuit includes a plurality of second transistors functioning as pass transistors. Note that the number of the first transistors is larger than the number of the second transistors, a gate of the first transistor is supplied with a first signal, and a gate of the second transistor is supplied with a second signal. The first circuit is supplied with grayscale signals through x input terminals, and the first circuit selects y grayscale signals of the grayscale signals with the first signal. The second circuit is supplied with y (y<x) grayscale signals, the second circuit outputs z (z<y) grayscale signals of the y grayscale signals to the output terminal with the second signal.