Variable Mode V-Drivers for Concurrent Charge Transfer
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Solution Overview
Problem
Conventional charge transfer methods in digital cameras require alternating operation of vertical and horizontal shift registers to avoid noise coupling, limiting the speed of charge transfer and resulting in lower resolution video capture due to the need for higher clock frequencies and increased image acquisition time.
Innovation Solution
Implementing a V-driver with adjustable drive strength and turn-on time that allows vertical shift registers to operate concurrently with the horizontal shift register, reducing noise coupling by using smaller switches and optimizing turn-on times, enabling simultaneous operation without corrupting image data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vertical and horizontal shift registers are operated alternately to avoid noise coupling, then image data corruption is prevented, but charge transfer speed is limited
Solution Approach 1:
The patent applies dynamics by making the vertical shift register operable in multiple modes: it can operate simultaneously with the horizontal shift register during horizontal operating intervals, or be selectively activated during horizontal non-operating intervals. This dynamic operation allows the system to adapt between speed optimization (simultaneous operation) and noise optimization (alternating operation), resolving the contradiction between charge transfer speed and image data quality
Solution Approach 2:
The patent changes the operational parameters of the vertical shift register by introducing variable timing control. Instead of fixed alternating operation, the vertical shift register's operation timing is adjusted based on noise coupling conditions and speed requirements. The controller can modify when the vertical shift register operates (during horizontal operating or non-operating intervals), enabling flexible parameter adjustment to balance speed and reliability
2Speed
If horizontal shift register operates at high frequency to transfer charge quickly, then charge transfer speed improves, but noise coupling increases when vertical shift registers operate simultaneously
Solution Approach 1:
The patent makes the vertical shift register operation dynamic rather than static. During horizontal operating intervals, the vertical shift register can remain inactive to avoid noise coupling with the high-frequency horizontal register. During horizontal non-operating intervals, the vertical shift register can be activated to transfer charge without interfering with horizontal operations. This dynamic timing adjustment allows the system to achieve high-speed horizontal transfer while minimizing noise coupling
Solution Approach 2:
The patent applies preliminary action by having the vertical shift register operate during horizontal non-operating intervals before the next horizontal transfer sequence begins. This timing allows charge to be pre-positioned in the vertical register during quiet periods, ready for subsequent horizontal transfer, thereby preparing the system in advance without causing noise interference during active horizontal operations
Data Source
AI summary
A method of transferring charge from a photosensitive array using a plurality of vertical shift registers, each having a plurality of vertical elements including first and last vertical element is disclosed The vertical shift registers are capable of transferring charge in a first direction from the first to the last vertical element The method also includes using at least one horizontal shift register having a plurality of horizontal elements. Each of the horizontal elements is arranged to receive charge transferred from the last vertical element of a respective one of the plurality of vertical shift registers, and shift the charge in a horizontal direction. The method includes operating the horizontal shift register during a plurality of horizontal operating intervals and operating the plurality of vertical shift registers during at least a portion of the plurality of horizontal operating intervals.