Avalanche Photodiode Counting Cutoff for Stable Low-Power Detection
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Solution Overview
Problem
Photon-count type photoelectric conversion devices face issues with high power consumption and unstable circuit operations due to the need for frequent photon detection operations, leading to unnecessary power usage and potential voltage drops, especially when the upper count limit is reached before the exposure period ends.
Innovation Solution
A photoelectric conversion device incorporating an avalanche multiplying photodiode with a control unit that generates photon detection pulses and a counter that stops avalanche current generation when a predetermined count value is reached, reducing power consumption and stabilizing circuit operations by controlling the applied voltage to the photodiode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the upper count limit value is reached before the exposure period ends, then the photon counting function is satisfied, but unnecessary power consumption occurs due to continued detection operations
Solution Approach 1:
The patent applies preliminary action by setting a predetermined upper count limit value before the exposure period ends. When the count value reaches this predetermined limit, the control unit proactively stops the detection operation in advance, preventing unnecessary power consumption that would occur if the system continued operating until the exposure period naturally ended. This resolves the contradiction by achieving complete photon counting (productivity) while avoiding wasteful energy consumption through early termination of operations.
2Productivity
If the frequency of photon detection operations is increased, then the photon counting capability is improved, but the power supply voltage drops due to increased current and interconnection resistance
Solution Approach 1:
The patent applies partial action by implementing a predetermined upper count limit that stops detection operations before the exposure period fully expires. This partial termination of operations reduces the cumulative current flow through power supply interconnections, thereby preventing voltage drops that would compromise circuit stability. The system achieves sufficient photon detection capability (productivity) through the counting operations that do occur, while avoiding the excessive action of continuous operation that would cause harmful voltage drops and reliability issues.
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 solution reduces power consumption and improves circuit stability by stopping avalanche current generation when the count value reaches a set threshold, minimizing unnecessary operations and voltage drops.
Implementation Method 1
an avalanche multiplying photodiode, a signal generation unit that includes a control unit configured to control an applied voltage to the photodiode and generates a photon detection pulse based on an output generated by incidence of a photon to the photodiode
Data Source
AI summary
A photoelectric conversion device includes an avalanche multiplying photodiode, a signal generation unit that includes a control unit configured to control an applied voltage to the photodiode and generates a photon detection pulse based on an output generated by incidence of a photon to the photodiode, and a counter that counts the photon detection pulse output from the signal generation unit, and the counter outputs a setting value detection signal when a count value of the photon detection pulse reaches a predetermined setting value, and in response to receiving the setting value detection signal, the control unit controls the applied voltage to the photodiode so as to stop generation of an avalanche current in the photodiode.