SPAD Sensing Apparatus Temperature Compensation
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Solution Overview
Problem
Single-photon avalanche detectors (SPADs) are sensitive to temperature and process variations, which can cause drift in breakdown voltage, leading to suboptimal operation and interference with communication band frequencies due to frequency drifts.
Innovation Solution
A sensing apparatus and method that adjust the oscillator frequency and voltage differential across SPADs based on temperature comparisons, using a processor to determine adjustment information for trimming the oscillator frequency and maintaining harmonics outside communication bands, thereby compensating for temperature variations and ensuring optimal SPAD operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the oscillator frequency is adjusted to avoid communication band frequencies, then interference with communication bands is prevented, but the device complexity increases due to additional frequency trimming mechanisms
Solution Approach 1:
The patent adjusts the oscillator frequency parameter based on temperature conditions to move harmonics away from communication band frequencies. The processor dynamically changes the operating frequency parameter of the oscillator, thereby avoiding harmful interference with communication bands without adding complex hardware filtering mechanisms.
Solution Approach 2:
The system implements a feedback mechanism where the processor monitors the oscillator frequency and its harmonics, compares them against communication band frequencies, and automatically adjusts the oscillator frequency to prevent interference. This closed-loop control eliminates the need for complex passive filtering circuits.
2Stability of the object's composition
If the voltage differential across SPADs is adjusted to compensate for temperature variations, then SPAD performance stability is improved, but the device complexity increases due to additional control circuits
Solution Approach 1:
The processor implements a feedback control system that monitors temperature conditions and automatically adjusts the voltage differential across the SPADs to maintain optimal breakdown voltage. This software-based feedback mechanism replaces complex hardware temperature compensation circuits while achieving stable SPAD performance across varying temperatures.
Solution Approach 2:
The system dynamically changes the voltage parameter applied to the SPADs based on temperature measurements. By adjusting the voltage differential parameter in response to temperature variations, the system maintains stable breakdown voltage and optimal detector performance without adding complex analog compensation circuits.
3Measurement precision
If temperature compensation is implemented for breakdown voltage drift, then measurement precision is improved, but the device complexity increases due to additional sensing and control mechanisms
Solution Approach 1:
The processor serves multiple functions: it controls the oscillator frequency, monitors temperature conditions, adjusts voltage differentials across SPADs, and processes distance measurements. By making the processor multi-functional, the patent avoids adding separate dedicated circuits for each function, thereby improving measurement precision without proportionally increasing device complexity.
Solution Approach 2:
The system dynamically adjusts the voltage parameter across the SPADs based on temperature to maintain accurate breakdown voltage operation, which directly improves distance measurement precision. This software-based parameter adjustment replaces complex hardware compensation mechanisms while enhancing measurement accuracy.
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 stabilizes SPAD performance across a wide temperature range, preventing interference with communication frequencies and ensuring accurate distance measurements by maintaining optimal operating conditions for the SPADs.
Implementation Method 1
The charge carrier may be released by the impact of a photon (impact ionization)
Implementation Method 2
A high reverse bias voltage generates a sufficiently large electric field such that a single charge carrier introduced into a depletion layer of the p-n junction device can cause a self-sustaining avalanche
Data Source
AI summary
A sensing apparatus includes a sensor and a processor. The sensor includes at least one light sensitive detector. The processor determines a first control value to control a voltage differential across the at least one light sensitive detector, and compares the first control value with a reference value associated with a reference temperature. Based on the comparison, the processor provides adjustment information for adjusting at least one output of the sensing apparatus, and an operating parameter of the sensing apparatus other than the voltage differential.