Graph Reader: Data Extraction and Verification from Datasheets

Why Are Datasheet Graphs Necessary?

Datasheet ratings are specified at a fixed test binning current. That is rarely the current at which the LED will operate in your luminaire. Comparing nominal flux from two datasheets tested at different binning currents does not tell you which item is superior in your specific application.

Engineering design requires knowing performance at your target current, solder-point temperature Ts, and LED count. Therefore, you must extract curve data, not just single table ratings.

Binning Current and Comparing Different LEDs

Binning current is the standard drive current at which a manufacturer measures nominal specs. Across different models, binning current varies widely: from tens of milliamps up to 150 mA, 350 mA, 700 mA, or higher.

Direct table-to-table flux comparisons can therefore be misleading. One LED might boast higher table flux simply because its test current was higher. Another might deliver superior efficacy or a more favorable forward voltage at your actual operating point.

Which Datasheet Curves Are Required for Calculation

Three primary curves from an LED datasheet are essential for engineering analysis.

First: Relative Luminous Flux vs. Forward Current. It illustrates how light output scales with current. Without it, normalizing different LEDs to a common operating current is impossible.

Second: Forward Voltage vs. Forward Current. Voltage rises with current. Even similar LEDs exhibit different Vf curves, directly impacting power consumption, driver sizing, and thermal load.

Third: Relative Luminous Flux vs. Temperature. Essential for modeling flux reduction at operating temperatures rather than 25 °C lab conditions. Operating luminaires always run hotter than 25 °C.

Graph Reader extracts curve points and readies them for calculation. This automated process provides an intuitive interface, eliminating imprecise manual visual estimation.

How Graph Reader Extracts Data from Curves

Graph Reader is not a generic plot digitizer. It is specifically built to extract engineering curve data needed for LED luminaire calculation and comparison, including non-English datasheets with legible graphs.

The tool converts PDF graphs into calibrated coordinate series. These datasets drive interpolation to determine flux and voltage at any chosen current.

Graph Reader prepares the data. Candidate comparison takes place in the calculator.

How Verification Works

Only verified curves are accepted by the calculator, preventing data errors from corrupting downstream engineering results. Graph Reader includes built-in verification tooling.

The UI displays the original PDF graph crop alongside the reconstructed vector curve for direct visual validation. You enter reference coordinates read from the original grid; the system computes deviation at those points.

Reference guidelines and interactive axis crosshairs assist in inspecting precise coordinates along the curve.

One reference pair is sufficient, but entering two pairs across different segments reduces calibration risk.

Accuracy, Limitations, and Manufacturer Data

The target digitization accuracy is ±2%.

If deviation exceeds target tolerance, users can report the discrepancy to assist model retraining.

Manufacturers publish data with inherent tolerances and measurement uncertainty. The service extracts and verifies document data, but cannot be held liable for manufacturer source accuracy.

A detailed explanation of the processing pipeline, confidence checks, and verification is provided in the methodology.

Data Transfer to the Calculator

Once extracted and verified, curve datasets feed directly into the calculator, enabling comprehensive engineering calculations.

This architectural separation ensures clear responsibilities: Graph Reader handles data extraction and verification; the calculator performs deterministic modeling. Without verified curves, calculations cannot proceed.

If you have not yet chosen candidate items, find them via LED Search, then send their datasheets for analysis. You can also upload PDF datasheets directly on this page.

FAQ

Why can't flux be compared using datasheet tables alone?

Table values reflect nominal binning currents, which differ across items. Real luminaires operate at distinct points requiring curve normalization.

What is binning current?

Binning current is the specific test current used by manufacturers to measure headline datasheet specs.

Which datasheet curves matter for calculation?

Primarily flux vs. current, forward voltage vs. current, and flux vs. temperature.

Why is manual verification required?

Verification ensures the reconstructed curve precisely matches the source document using reference points and error metrics.

How many reference points should I specify?

One pair is required; two pairs across different curve segments provide higher confidence.

What happens after data extraction?

Verified curves can be pushed to /calculator to compare candidate performance. Unverified data cannot be transferred.