Pixel Cell Current Differencing for Fast Charge Measurement
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Solution Overview
Problem
Current technologies face challenges in efficiently determining the quantity of charge on capacitive elements, particularly in high-demand applications like image processing and sensor data processing, where quick and efficient processing of large data volumes is necessary.
Innovation Solution
A device and method for determining the amount of charge on a capacitive element, utilizing a pixel cell with a photosensor, power storage device, and switching unit for efficient charge measurement and processing, including integrated preprocessing in CMOS image sensors, and a method for determining the position of a maximum in an amplitude modulated signal by sampling and digitizing difference values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional charge measurement methods are used, then measurement capability is provided, but processing speed and efficiency are insufficient for high-demand applications
Solution Approach 1:
The patent applies preliminary action by performing difference formation between successive measurement currents in the pixel cell before readout. The first measurement current is stored in a storage element, and the difference between the first and second measurement currents is calculated and stored. This preprocessing of charge data at the pixel level enables faster subsequent processing while maintaining measurement accuracy, directly resolving the contradiction between processing speed and measurement precision.
2Productivity
If more complex processing circuits are added to improve processing capability, then data processing efficiency increases, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into the pixel cell structure: the photosensor generates measurement current, the storage element stores the first measurement current, and the switching unit performs difference formation by combining the first and second measurement currents. This integration of generation, storage, and processing functions within the pixel cell achieves efficient data processing without adding separate complex processing circuits, thereby resolving the contradiction between productivity and device complexity.
3Measurement precision
If integration time is extended to improve measurement accuracy, then charge measurement precision improves, but temporal resolution and processing speed deteriorate
Solution Approach 1:
The patent applies partial action by performing difference formation on successive measurement currents rather than requiring complete integration of all measurement parameters. By calculating the difference between first and second measurement currents, the system achieves sufficient measurement precision for detecting changes in radiation or chemical concentration without requiring extended integration times, thus maintaining temporal resolution and processing speed.
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
Enables more efficient collection and processing of data, improving the accuracy and speed of charge measurement in capacitive elements, particularly in image processing and sensor applications.
Implementation Method 1
a photosensor (110) which is designed to generate a measurement current (IDPh) depending on radiation (L) incident on the pixel cell (100)
Data Source
Figure 1
Figure 2~3
Figure 4A
AI summary
The pixel cell (100) has an output (102), a photo sensor (110) that is formed to produce a radiation in a measuring cycle of a measuring current and in another measuring cycle of another measuring current, and an output node (104). A current storage device (120) is so formed that a curent is embossed by the current stroage device dependent of the former measuring current in a operation mode. A switch unit (130) is formed to form a difference of the embossed current and the latter measuring current at the output node in a selection cycle and to couple the output node with the output. Independent claims are also included for the following: (1) a method for operating a pixel cell (2) a method for determining the position of the maximum on the envelope of an analogue amplitude modulation signal (3) a device for determining a load (4) a device for determining the load of a capacitive element (5) a method for determining the load of a capacitive element (6) a device for setting a circuit node to a predetermined voltage (7) a method for setting a circuit node to a predetermined voltage (8) a device for charge-based analog or digital transformation (9) a method for charge-based analog or digital transformation (10) a device for charge-based signal processing (11) a method for charge-based signal processing (12) a computer program with a program code.