Pixel Differential Input Circuit With Enable-Gated Current Control
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Solution Overview
Problem
Conventional solid-state imaging elements with differential input circuits for each pixel consume high power due to constant current flow even when some pixels are excluded from readout, as stopping the power supply voltage is not desirable due to stabilization time issues.
Innovation Solution
A solid-state imaging element with a current source circuit that supplies a constant current only when enabled, using differential transistors and a digital signal generating unit to process the differential amplified signal, and a logic gate to control the enable signal for power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the power supply voltage is stopped to reduce power consumption during pixel exclusion, then power consumption is reduced, but the power supply voltage takes time to become stable after being turned on again
Solution Approach 1:
The patent applies dynamics by making the constant current supply controllable and adjustable based on operational needs. The constant current source is configured to supply current only to active pixels, allowing the system to dynamically adapt its power consumption and current distribution according to the readout status of different pixel regions.
Solution Approach 2:
The patent implements local quality by differentiating the constant current supply between different pixel regions. When some pixels are excluded from readout, the constant current is supplied only to the remaining active pixels rather than uniformly to all pixels, thereby reducing overall power consumption without affecting the performance of active pixels.
2Speed
If a constant current source is disposed in the differential input circuits for each pixel, then high-speed readout is achieved, but power consumption increases when some pixels are excluded from readout
Solution Approach 1:
The patent applies local quality by making the constant current supply selective and differentiated across pixel regions. The constant current source is configured to supply current only to active pixels that are being read out, while excluding current supply to pixels that are not being read out. This maintains high-speed readout performance for active pixels while reducing overall power consumption.
Solution Approach 2:
The patent implements dynamics by making the constant current supply controllable and adaptable. The system can dynamically adjust which pixels receive constant current based on the readout configuration, allowing flexible control over both performance and power consumption characteristics.
Data Source
AI summary
Power consumption is reduced in a solid-state imaging element including a differential input circuit for each pixel.The solid-state imaging element includes a current source circuit, a pair of differential transistors, and a digital signal generating unit. The current source circuit in the solid-state imaging element supplies a predetermined constant current in a case where a predetermined enable signal is input. The pair of differential transistors generates a differential amplified signal using the constant current, the differential amplified signal being obtained by amplifying a difference between an analog signal generated by a pixel circuit and a predetermined reference signal. The digital signal generating unit generates a digital signal from the differential amplified signal.