Shared Source Follower Circuit for High-Density pH Imaging
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Solution Overview
Problem
The existing pH detecting devices require a large number of transistors and wirings per pixel, limiting high-integration capabilities and increasing the wiring area, which hampers the development of high-density pixel arrays for two-dimensional pH distribution imaging.
Innovation Solution
The solution involves sharing source follower and reset circuits across multiple pixels, synchronizing the TG section control lines to allow simultaneous operation, and selectively activating sensing sections to reduce the number of transistors and wirings needed, while maintaining accurate charge detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If each pixel has dedicated source follower and reset circuits, then charge detection accuracy is maintained, but device complexity and wiring area increase
Solution Approach 1:
The patent merges source follower circuits and reset circuits into shared resources that serve multiple pixels simultaneously. Specifically, a single source follower circuit processes signals from multiple pixels sequentially, and reset circuits are shared across pixel groups, dramatically reducing the number of transistors and wirings required per pixel while preserving detection accuracy through time-multiplexed operation
Solution Approach 2:
The invention makes circuits universal by designing source follower and reset circuits that can serve multiple pixels rather than being dedicated to single pixels. The shared circuits are controlled by pixel selection signals that route different pixels to the same circuit resources at different times, enabling one circuit to perform the function of multiple dedicated circuits
2Measurement precision
If more transistors and wirings are provided per pixel, then charge detection accuracy improves, but integration density decreases
Solution Approach 1:
By merging dedicated circuits into shared resources that serve multiple pixels, the patent reduces the transistor and wiring count per pixel, thereby increasing the number of pixels that can be integrated in a given area. The time-multiplexed architecture ensures that sharing does not compromise detection accuracy
Solution Approach 2:
The patent transitions from a spatial allocation of circuits (one circuit per pixel) to a temporal allocation (one circuit serving multiple pixels over time). This dimensional shift from space to time allows higher integration density while maintaining the functional capability of dedicated circuits
3Manufacturing precision
If TG section control lines are independently controlled per pixel, then selective charge transfer precision improves, but wiring area increases
Solution Approach 1:
The patent merges multiple independent TG control lines into a shared control mechanism. Instead of having separate control lines for each pixel, a single control line with pixel selection signals controls the TG sections of multiple pixels sequentially, reducing wiring area while maintaining precise selective charge transfer through time-multiplexed control
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the number of transistors and wirings per pixel, enabling higher integration density without compromising pixel density and allowing for efficient two-dimensional pH distribution imaging.
Implementation Method 1
the depth of the potential well 15 is changed in a region, namely a p-type diffusion region 72 of a silicon substrate 71 faced with the sensing film 12 in accordance with the concentration of hydrogen ions
Implementation Method 2
the charge in the ID section 21 is transferred to the potential well 15 of the sensing section 10 with the potential of the ICG section 23 controlled
Implementation Method 3
the charge charged in the potential well 15 of the sensing section 10 is transferred to the FD section 33 with the voltage of the TG section 31 controlled to change a potential of a region of the silicon substrate 71
Implementation Method 4
The charge stored in the FD section 33 is detected by a charge quantity detecting section 40. As such a charge quantity detecting section 40, a source follower type signal amplifier can be used
Implementation Method 5
the charge stored in the FD section 33 is transferred to the RD section 53 with the voltage of the RG section 51 controlled to change a potential of a region of the silicon substrate 71
Data Source
Figure 1(A)~1(B)
Figure 2(A)~2(F)
Figure 3
AI summary
Provided are a device for detecting chemical and physical phenomenon suitable for high integration, and a method therefor. Rather than using a TG section signal to select pixels that require charge measurement, the on-off timing (the timing for moving the charge from a sensing section to an FD section) of the TG section is harmonized for all pixels, and the release or injection of the charge to the sensing section is separately controlled, whereby the charge is held only in sensing sections of pixels that require charge measurement, and the charge is emptied in sensing sections of pixels that do not require charge measurement. In this state, the TG section of all pixels can be opened at the same time, whereby the charge is transferred to the FD section from only the sensing sections holding a charge, and the charge level of the pixel is detected.