Avalanche Photodiode Pixel Array Power Management
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Solution Overview
Problem
The existing photoelectric conversion apparatuses with avalanche photodiodes (APDs) face high power consumption when all pixels transition to a standby state simultaneously, leading to increased peak power usage.
Innovation Solution
The apparatus includes a first and second pixel with photodiodes configured for avalanche multiplication, along with a signal processing circuit that controls the photodiodes to be in a standby state or recharge state, using a pulse signal to manage power consumption by shifting the timing of recharge operations across pixels, thereby reducing simultaneous power draw.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all APDs in a pixel array are simultaneously caused to transition to a standby state, then the photoelectric conversion apparatus can maintain uniform operation across all pixels, but the peak value of power consumption is increased due to simultaneous recharge currents
Solution Approach 1:
The pixel array is divided into multiple groups, and the standby state transition timing is segmented across different groups. Each group transitions to standby state at different times, which distributes the recharge currents over time and reduces peak power consumption while maintaining uniform operation across all pixels.
Solution Approach 2:
The patent implements periodic standby state transitions for different pixel groups. By controlling the timing of standby state transitions in a periodic manner across multiple groups, the recharge currents are distributed over time periods, preventing simultaneous current peaks and reducing overall peak power consumption.
2Device complexity
If all APDs transition to standby state at the same time, then the control circuit operation is simplified, but simultaneous recharge currents cause high peak power consumption
Solution Approach 1:
The pixel array is segmented into multiple groups with different standby transition timings. This segmentation allows the control circuit to manage groups separately, maintaining relatively simple control logic while distributing the power consumption peaks across different time periods, thus reducing peak power consumption without significantly increasing control circuit complexity.
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 peak value of power consumption by staggering the recharge currents across pixels, resulting in a more efficient and flattened power consumption profile.
Implementation Method 1
a photodiode configured to perform avalanche multiplication
Implementation Method 2
a photocarrier due to a single photon causes avalanche multiplication
Data Source
AI summary
A photoelectric conversion apparatus includes a first pixel and a second pixel, each of which includes a photodiode, and a signal processing circuit including a control circuit and a counter. The control circuit is connected to the photodiode and a circuit configured to generate a pulse signal, and performs control, based on the pulse signal, so as to be in a standby state or a recharge state. The counter counts the number of periods in which avalanche multiplication has occurred in the standby state. A third pulse of the pulse signal for the second pixel is input to the control circuit in a period from when a first pulse of the pulse signal for the first pixel is input to the control circuit to when a second pulse of the pulse signal for the first pixel subsequent to the first pulse is input to the control circuit.