Capacitor-Based Histogram Generation for Low-Power Event Detection

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Solution Overview

Problem

Existing histogram generation methods face challenges in achieving high resolution while maintaining low power consumption and cost, particularly in time-critical applications like fluorescence decay time measurements, due to high power consumption and bulkiness associated with multiple Time to Digital Converters (TDCs) and complex digital gate operations.

Innovation Solution

A signal processing method that connects event detectors to a current injection module and capacitors, where each capacitor stores charge corresponding to event signals, reducing data volume and power consumption by eliminating the need for high-frequency digital gate operations, and allowing independent control for each event detector.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple Time to Digital Converters (TDCs) are used for high-resolution histogram generation, then measurement precision is improved, but device complexity and production cost increase

Engineering Contradiction:
Improvehistogram resolutionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the functionality of multiple TDCs into a single TDC by using capacitors to parallelly store charge from multiple event detectors. The TDC converts timestamps from only one detector at a time, while capacitors accumulate charges representing event counts from all detectors. This combination achieves the same histogram generation capability as multiple TDCs but with reduced device complexity and cost.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Capacitors are introduced as intermediary elements between event detectors and the TDC. Instead of each detector connecting directly to a TDC, detectors connect to capacitors that accumulate charge, and the TDC only needs to read from one capacitor at a time. This intermediary approach enables high-resolution histogram generation without requiring multiple TDCs.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If multiple Time to Digital Converters (TDCs) are used for high-resolution histogram generation, then measurement precision is improved, but production cost increases

Engineering Contradiction:
Improvehistogram resolutionVSAvoidproduction cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges the functionality of multiple TDCs into a single TDC by using capacitors to parallelly store charge from multiple event detectors. The TDC converts timestamps from only one detector at a time, while capacitors accumulate charges representing event counts from all detectors. This combination achieves the same histogram generation capability as multiple TDCs but with reduced device complexity and cost.

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If complex digital gate operations are performed at high frequency rates, then productivity is improved, but power consumption increases

Engineering Contradiction:
Improveframe rateVSAvoidpower consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent extracts the complex digital gate operations and high-frequency timestamp conversions from the main processing path. Instead of performing these operations continuously for all detectors, the system uses simple charge accumulation in capacitors during the integration period, and only performs TDC conversion for one detector at a time. This extraction reduces power consumption while maintaining high frame rate capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system uses periodic action by having the TDC operate only during specific time windows when reading from one capacitor at a time, rather than continuously operating at high frequency for all detectors. The capacitors continuously accumulate charge in parallel, but the power-intensive TDC conversion happens periodically for a single detector, reducing overall power consumption while maintaining productivity.

Inventive Principle:
Principle #19Periodic action

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 enables high-resolution histogram generation with low power consumption and reduced production costs, suitable for time-critical applications like fluorescence decay time measurements, by directly linking charge accumulation in capacitors to event counts and allowing for high frame rates.

Implementation Method 1

a current injection module which is connected to a plurality of capacitors, wherein the histogram to be generated comprises a plurality of bins and each of the bins is univocally assigned to a capacitor among the plurality of capacitors

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3365975B1Signal processing method for histogram generation, and corresponding device and use
Publication Date: 2019.08.28 UNIV DE BARCELONA
  • EP3365975B1 patent drawingFigure 1
  • EP3365975B1 patent drawingFigure 2
  • EP3365975B1 patent drawingFigure 3

AI summary

Signal processing method for histogram generation, and corresponding device and use. A signal processing method for histogram generation from a plurality of event detectors, that generate event signals as a response to external events, and are connected to a current injection module which is connected to a plurality of capacitors, wherein each histogram bin is univocally assigned to a capacitor. The method comprising the steps of: during an event time interval corresponding to a bin, the event detectors generate event signals as a response to external events; the current injection module detects said event signals; for each event signals, the current injection module generates a corresponding current signal, and said current signal is injected in a capacitor assigned to said bin, and stored therein; repeating steps for each successive bin of said histogram. And reading the charge accumulated in each of said capacitors.