Image Sensor Photo Gate Driver Phase Adjustment for PVT Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current image sensors face challenges in accurately calculating depth information due to power, voltage, and temperature (PVT) noise, which affects the quality of depth image data, especially in time-of-flight (TOF) methods.
Innovation Solution
The method involves generating demodulated signals for an image sensor's pixel array, adjusting their phase using a source clock signal to remove PVT noise, and applying these phase-adjusted signals to the array, while transmitting both demodulated and reference clock signals on the same PVT conditions, with the source clock signal having an opposite phase to the reference clock signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase adjustment using source clock signal is applied to remove PVT noise, then measurement precision of depth information is improved, but device complexity increases
Solution Approach 1:
A source clock signal is introduced as an intermediary to mediate between the reference clock signal and the demodulated signals. This source clock signal serves as a common reference that both generates the demodulated signals and adjusts their phases, eliminating PVT noise without requiring complex independent adjustment circuits for each signal path.
Solution Approach 2:
The phase of demodulated signals is adjusted by changing the timing parameter relative to the source clock signal. By varying the phase alignment with the source clock, the signals are synchronized to remove PVT noise while maintaining the ability to extract accurate depth information through phase differences.
2Reliability
If multiple demodulated signals are generated and phase-adjusted, then reliability of depth information is improved, but manufacturing precision requirements increase
Solution Approach 1:
All demodulated signals are referenced to the same source clock signal, creating an equipotential reference plane. This ensures that all signals experience identical PVT conditions and timing references, making them inherently synchronized and eliminating the need for high-precision independent adjustment of each signal path.
Solution Approach 2:
The source clock signal provides a periodic reference that naturally synchronizes all demodulated signals. By using the periodic cycles of the source clock as the adjustment basis, the system achieves reliable phase alignment without requiring complex continuous adjustment mechanisms, thereby reducing manufacturing precision requirements.
Data Source
AI summary
An image sensor includes a photo gate controller configured to generate a plurality of demodulated signals respectively corresponding to a plurality of rows of a pixel array and a photo gate driver configured to adjust a phase of the demodulated signals using a source clock signal to remove power, voltage and temperature (PVT) noise and to apply the phase-adjusted demodulated signals to the pixel array. The image sensor matches the phases of the respective demodulated signals using the source clock signal generated based on a reference clock signal, thereby increasing the quality of depth images.