SPAD Photodetector Voltage Control Using Amplitude Spectrum Minima
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Solution Overview
Problem
Existing photodetectors face challenges in efficiently stabilizing the voltage for groups of single photon avalanche diodes (SPADs), leading to suboptimal operating conditions, premature saturation, and reduced sensitivity to small photon rates.
Innovation Solution
A method and system for voltage stabilization of SPADs in a photodetector, where a digitizer is connected downstream of each diode, and the blocking voltage is controlled based on ascertained local minima of the amplitude spectrum of detected signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional voltage stabilization methods are used for SPADs, then the voltage can be maintained at a fixed level, but the dead time cannot be efficiently controlled and optimal operating conditions cannot be ensured
Solution Approach 1:
The patent implements a feedback mechanism where the dead time of SPADs is measured and used to adjust the blocking voltage. The control device continuously monitors the dead time parameter and modifies the voltage to maintain optimal operating conditions, resolving the contradiction between voltage stability and dead time control efficiency.
Solution Approach 2:
The patent changes the operating parameter from fixed voltage to dynamically adjusted voltage based on dead time measurements. By varying the blocking voltage according to measured dead time values, the system achieves both stable operation and efficient dead time control, improving productivity without sacrificing reliability.
2Device complexity
If fixed blocking voltage is applied to SPADs, then circuit design is simplified, but tolerance and aging effects cannot be compensated leading to premature saturation
Solution Approach 1:
The control device uses feedback from dead time measurements to automatically compensate for tolerance and aging effects. This dynamic adjustment prevents premature saturation of the photodetector while maintaining a relatively simple circuit architecture, resolving the contradiction between device complexity and reliability.
Solution Approach 2:
The system performs self-adjustment by using its own dead time measurements to control the blocking voltage. This self-service mechanism compensates for aging and tolerance effects without requiring external calibration or complex control circuits, improving reliability while keeping device complexity manageable.
3Ease of operation
If fixed blocking voltage is used, then manufacturing and operation are simpler, but sensitivity to small photon rates is reduced
Solution Approach 1:
The patent adjusts the blocking voltage parameter based on measured dead time to optimize sensitivity for detecting small photon rates. This dynamic parameter adjustment maintains ease of operation through automated control while significantly improving measurement precision for low photon rate detection.
4Ease of operation
If conventional voltage control is used, then system operation is straightforward, but premature saturation occurs reducing detection capability
Solution Approach 1:
The system uses feedback from dead time measurements to automatically adjust voltage and prevent premature saturation. This maintains straightforward operation through automated control while preserving detection capability by keeping the photodetector in its optimal operating range.
Solution Approach 2:
The control device performs preliminary adjustment of the blocking voltage based on initial dead time measurements to prevent saturation before it occurs. This preliminary action maintains detection capability while keeping system operation simple through automated prevention of problematic states.
Data Source
AI summary
A method for voltage stabilization of one or more groups of single photon avalanche diodes of a photodetector, wherein a digitizer is connected downstream of each diode. The method includes: detecting one or more signals of a signal path of the photodetector, which signal path comprises the diodes and the digitizers, with the same blocking voltage applied to the diodes; ascertaining a particular amplitude spectrum of the one or more detected signals; ascertaining a particular local minimum of the ascertained amplitude spectrum or spectra; controlling the applied blocking voltage based on the ascertained local minimum or minima.