SPAD Light Receiving Circuit Dynamic Voltage Control
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Solution Overview
Problem
Existing distance measuring devices using time of flight (ToF) technology face challenges in minimizing dead time during photon detection, which affects measurement accuracy and efficiency.
Innovation Solution
A light receiving device with a control circuit that adjusts power supply potential and recharge current parameters based on signal output from the light receiving circuit, including error detection and correction, to minimize dead time and improve measurement performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the voltage across the terminals of the SPAD is lowered to stop the avalanche phenomenon (quenching), then the dead time is reduced, but the reliability of photon detection may be compromised
Solution Approach 1:
The patent applies dynamics by making the voltage across the SPAD terminals variable rather than fixed. The control circuit dynamically adjusts the voltage based on the operational state - maintaining breakdown voltage during normal detection and lowering it during quenching periods. This dynamic voltage adjustment allows the system to optimize between detection reliability and dead time reduction at different moments in time.
Solution Approach 2:
The patent implements feedback through the control circuit that monitors the output signal from the light receiving circuit and uses this information to adjust the voltage across the SPAD. When a photon detection event occurs, the feedback mechanism triggers voltage reduction to stop the avalanche phenomenon, and subsequently restores the voltage to breakdown level to prepare for the next detection. This closed-loop feedback system ensures reliable operation while minimizing dead time.
2Loss of time
If the power supply potential is increased to improve recharge speed, then the dead time is reduced, but the energy consumption increases
Solution Approach 1:
The patent applies dynamics by making the power supply potential variable rather than constant. The control circuit adjusts the power supply potential based on the operational state of the light receiving circuit - providing higher potential during recharge periods to reduce dead time, and reducing it during normal operation to minimize energy consumption. This dynamic adjustment optimizes the trade-off between recharge speed and energy usage.
Solution Approach 2:
The patent changes the parameter of power supply potential to optimize system performance. By varying the power supply potential according to operational requirements, the system can achieve faster recharge speeds when needed (reducing dead time) while maintaining lower energy consumption during steady-state operation. This parameter optimization is achieved through the control circuit's intelligent adjustment based on feedback signals.
3Productivity
If the recharge current is increased to reduce dead time, then the measurement efficiency is improved, but the error rate in signal detection increases
Solution Approach 1:
The patent implements feedback through the control circuit that monitors the output signal from the light receiving circuit and uses this information to adjust the recharge current. The feedback mechanism allows the system to optimize the recharge current based on actual detection conditions, reducing dead time when possible while avoiding excessive current that would cause detection errors. The control circuit continuously tunes the recharge current to maintain optimal balance between efficiency and accuracy.
Solution Approach 2:
The patent changes the parameter of recharge current to optimize the balance between measurement efficiency and detection accuracy. By dynamically adjusting the recharge current based on operational state and feedback signals, the system achieves faster recharge (improved efficiency) without exceeding the threshold that would cause signal detection errors. This parameter optimization allows the system to adapt to varying operational conditions.
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
The solution effectively reduces dead time and enhances the accuracy and efficiency of distance measurements by optimizing the operation of the light receiving device.
Implementation Method 1
a light receiving circuit including a light receiving element... in a reaction with a photon
Implementation Method 2
a voltage equal to or higher than a breakdown voltage is applied across terminals, and an avalanche phenomenon occurs due to incidence of a single photon
Data Source
AI summary
Provided are a light receiving device, a light receiving circuit, and a distance measuring device capable of minimizing dead time.A light receiving device according to the present disclosure may include: a light receiving circuit including a light receiving element; a power supply circuit configured to supply a power supply potential to the light receiving circuit; and a control circuit configured to control the power supply potential supplied by the power supply circuit on the basis of a signal output from the light receiving circuit in a reaction with a photon.