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Power Base — Charger Test

In-house design verification (DVT) of the supplier's USB-charger prototype for the EverTag Power Base Module (article 232507). An automated bench harness exercises the charger's DC output (and its ripple) and produces a per-run test report with graphs and a PASS/FAIL verdict for every measurement.

Scope — design verification, not certification

This is an early engineering check that the prototype holds the 5 V / 2 A (10 W) envelope with margin. It does not replace the supplier's UL 498 / UL 1310 / UL 62368-1, FCC Part 15B, and DoE Level VI work — see US Charger (232507) §3.

This page covers what we verify and the acceptance criteria & basis. The how (instrument hookup, cut-USB-C wiring, SCPI, command-line flags, instrument quirks) lives with the tool so it stays in sync with the code — see §4.

1. What we verify

The 232507 output is an isolated flyback, Class 2-limited, 5 V / 2 A (10 W), USB-C, no PD; both USB-C receptacles share one 10 W rail.

Test Question it answers
Load regulation Does the output hold 5 V ±5% from no load to the rated 2 A?
Output current capability Can it actually deliver 2 A while staying in regulation?
OCP / current limit Where does it current-limit, and how gracefully (clamp / foldback / hiccup)?
Short-circuit + recovery Does protection engage on a short, and does the output recover when cleared?
Soak (5 min @ 2 A) Is it stable under sustained full load (voltage droop, thermal foldback, trips)?
Output ripple (scope) Is output ripple/noise within the engineering target?

2. Acceptance criteria & basis

Agree these before the run; deviations go back to the supplier. Each limit is tied to what is actually expected of a 5 V / 2 A USB source, with the governing standard.

Criterion Target Basis / reference
Output voltage regulation 5 V ±5% (4.75–5.25 V), 0 → 2.0 A USB 2.0 source VBUS at the connector (4.75–5.25 V); within USB Type-C vSafe5V (4.75–5.5 V)
Output current capability ≥ 2.0 A at ≥ 4.75 V Rated 5 V / 2 A (10 W); USB Type-C natively supports up to 5 V / 3 A
OCP / current-limit knee > 2.2 A, graceful & recoverable (CC clamp / foldback / hiccup) UL 1310 (Class 2) + UL/IEC 62368-1 over-current protection
Short-circuit Trips, then recovers to 5 V when cleared UL 1310 / UL 62368-1 short-circuit protection
Soak (2 A, 5 min) Vout stable, no thermal foldback, no trip UL/IEC 62368-1 temperature-rise / component derating
Output ripple (if measured) ≤ 100 mVpp (AC, 20 MHz BW) Engineering target — no hard USB source ripple limit; mains-side switching noise is covered separately by FCC Part 15B

Why 5 V ±5% and not ±10%?

The ±5% band (4.75–5.25 V) is the USB voltage requirement for a source, measured at the connector (USB 2.0; also inside USB Type-C vSafe5V, 4.75–5.5 V). The looser ~−10% / 4.40 V number is the device-end minimum a sink must tolerate after cable and connector IR drop — a receiver allowance, not a source spec. As the supply, the charger is held to the tighter source band so the device still sees ≥ 4.40 V once the cable drop is subtracted. (USB 2.0 also raised the absolute max to 5.5 V by the 2014 ECN.)

Formal vs bench

OCP, short-circuit and temperature limits are formally verified during the supplier's UL 1310 / UL 62368-1 evaluation. This bench test is an early engineering check that the design has margin, not the certification itself. Efficiency / no-load (DoE Level VI) and true case/junction temperature are out of scope here — they need an AC power meter and thermocouples/IR.

3. Prerequisites

Before a run:

  • Charger powered from the intended AC source and input voltage/frequency — record both (e.g. 240–110 V AC travel adapter, 115 V / 50 Hz). Note which receptacle and orientation is under test (both share one 10 W rail).
  • A cut USB-C cable with VBUS and GND positively identified by continuity to the connector pins (see box below) — not by voltage: an unconnected data wire shows a misleading "phantom" voltage on a high-impedance meter.
  • 4-wire (Kelvin / remote-sense) hookup. A separate sense pair is tapped at the charger's USB-C output and landed on the load's SENSE (S+/S−) terminals, so the output voltage is read at the charger and the force-lead/cable drop is excluded. Land the force pair (high current) and the sense pair before starting; keep the force leads short and thick.
  • Instruments on the LAN (DL3021 load; MSO5000 scope for ripple) and a host PC with the harness.

USB-C output — which pins carry power

On the charger's USB-C receptacle, power is on dedicated pins; the rest are data/config and must not be wired to the load.

Function Pins Load test
VBUS (+5 V) A4, A9, B4, B9 Yes — force/sense +
GND A1, A12, B1, B12 Yes — force/sense −
CC1 / CC2 (VCONN) A5 / B5 No — orientation / USB-PD (this charger needs no Rd to output 5 V)
D+ / D− A6/B6, A7/B7 No — USB 2.0 data
SuperSpeed pairs A2/A3, A10/A11, B2/B3, B10/B11 No — high-speed data
SBU1 / SBU2 A8 / B8 No — sideband / Alt Mode

The four VBUS pins (and four GND pins) are normally bonded together inside the cable, so a cut cable may present them as one or several conductors — always confirm by continuity. The 232507 is a supplier module with no in-house PCB page, so this connector reference lives here with the test; mechanical details are under Mechanical → Supplier Deliverables → Power Base Module.

4. How it's run

A Python harness drives a Rigol DL3021 DC electronic load over LAN (and, optionally, a Rigol MSO5000 oscilloscope for ripple). It steps the load through the tests above while logging V / I / P, then auto-generates a Markdown report with one graph per measurement and a computed PASS/FAIL per criterion.

The exact procedure — instrument IPs, the cut-USB-C 4-wire (remote-sense) wiring, ripple-probe setup, SCPI details, command-line flags and known instrument quirks — is documented with the tool, next to the code it controls:

  • Harness + full procedure: tools/power-base-charger-test/ (see its README.md)
  • Per-run output: results/run_<rev>_<timestamp>/ — CSV logs, a PNG per measurement, the ripple scope capture, and a self-contained protocol.md.

5. Test reports

Each prototype run is published as its own dated report (PCB revision, port, conditions, graphs, per-test results and an overall verdict). All runs use 4-wire (remote-sense) measurement, so output voltages are read at the charger terminals.

Date PCB rev Port Sample Knee (A) Reg. within ±5%? Short recovers? Soak stable? Verdict
2026-06-09 10001135-V1 Upper USB-C prototype 260609-1 ~2.57 Yes Yes Yes PASS
2026-06-09 10001135-V1 Lower USB-C prototype 260609-1 ~2.53 Yes Yes Yes PASS