USB Analyzer Design
Worked for 7 mins 56 sec
El movimiento quedó aplicado y eliminó las trazas colgantes, pero abrió 22 airwires porque el router quirúrgico no puede distinguir los tres pads
IN duplicados de U2. Haré un último pase global permitido tras el cambio de colocación y después revisaré DRC nuevamente.Thought for 1 min 58 sec
El nuevo preflight detectó una traza con ancho inferior al mínimo aceptado por el motor (
wires[156].width). Localizaré esa traza de 0,10 mm, la eliminaré o corregiré a 0,15 mm y volveré a comprobar antes de otro intento.Worked for 4 mins 43 sec
Moví
U2 y sus pasivos asociados 2,5 mm hacia arriba, conservando orientación y agrupación. También eliminé las trazas locales obsoletas y dejé 0 trazas colgantes en esa etapa.Estado pendiente
- 22 airwires
- 5 solapes de cobre alrededor de U2 y otros pads
- La barra común de los tres
U2:INaún no está construida TPS_ILIMyTPS_FAULT_Nsiguen sin ruta- El auto-router no puede reiniciarse por una traza inválida con ancho menor al permitido:
wires[156].width, probablemente una conexión local de 0,10 mm
No pude localizar/corregir esa traza porque se agotaron los ACUs. El siguiente paso es corregirla a 0,15 mm o eliminarla si está obsoleta, repetir preflight y ejecutar un nuevo pase de routing seguido de DRC.
Corregir traza inválida
Localizar wires[156]
Revisar solapes U2
Reconstruir U2 IN
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Ask about this doc
Board Bring-Up Plan — USB Power Analyzer V1
Prerequisites
- Equipment: current-limited bench supply, multimeter, oscilloscope if available, electronic load or power resistors, USB test device, USB cable for RP2040 firmware header, thermometer/IR camera if available.
- Firmware: see
Firmware Starterfor the initial RP2040 firmware. - Safety: do not use a laptop USB port as the first 2 A source. Start with a bench supply and current limit.
- Critical note:
U1:VBATis intentionally unused. Do not connect RP2040 StampVBATto USB 5 V; datasheet range is LiPo 3.6–4.2 V.
1. Visual Inspection
- Verify orientation of U2 TPS2559DRCR, U3 INA226, D1 USBLC6-2SC6, Q1 MMBT3904, D2/D3/D4 LEDs, BZ1, J1/J2/J3.
- Check for solder bridges on TPS2559 VSON pins and exposed pad.
- Verify R1 shunt value is 20 mΩ and rated for at least 1 W.
- Verify R2 is 49.9 kΩ for TPS2559 ILIM.
- Verify I2C pull-ups R4/R5 are 4.7 kΩ to 3V3, not 5 V.
- Verify R3/R19 pull-ups for FAULT/ALERT are to 3V3.
2. Unpowered Continuity Checks
Table
| Check | Expected Result | Stop If |
|---|---|---|
| VBUS_PROTECTED to GND | No short | Low-ohm short |
| VBUS_SWITCHED to GND | No short | Low-ohm short |
| VBUS_DUT to GND | No short | Low-ohm short |
| 3V3 to GND | No short | Low-ohm short |
| VBUS_PROTECTED to U1:VBAT | No continuity | Any continuity |
| 5V/VBUS to 3V3 | No short | Any short |
| USB_DUT_D_P to USB_DUT_D_N | No short | Any short |
| USB_DUT_D_P / USB_DUT_D_N to VBUS or GND | No short | Any short |
| J3 firmware VBUS to J1/J2 VBUS | Verify intended connection before dual-USB use | Unexpected backfeed path |
3. Power Rail Verification
Table
| Rail | Source | Expected Voltage | Tolerance | Measure At | Current Limit | Pass Criteria |
|---|---|---|---|---|---|---|
| USB_IN_VBUS_RAW | J1 pin 1 before F1 | 5.0 V | USB source dependent | J1 pin 1 | 50–100 mA first power | Stable, no heating |
| VBUS_PROTECTED | F1 output / U2 IN / U1 5V | 5.0 V minus PTC drop | Depends on load | U2 IN, U1 5V | 50–100 mA initial | RP2040 powers without overcurrent |
| 3V3 | U1 RP2040 Stamp LDO output | 3.3 V | ±2–5% | U1 3.3V, C5 | Observe only | 3.23–3.37 V typical |
| VBUS_SWITCHED | U2 OUT before shunt | 0 V when EN low, ~5 V when EN high | Load dependent | U2 OUT, C2/C3 | Start unloaded | OFF by default, ON only by firmware |
| VBUS_DUT | R1 load side / J2 VBUS | ~5 V when enabled | Load dependent | J2 VBUS | Step to 2 A only after validation | Drop across R1 ≈ 40 mV at 2 A |
Procedure:
- With no DUT attached, apply 5.0 V from a bench supply to the input path with a 50–100 mA current limit.
- Confirm 3V3 appears and is stable.
- Confirm TPS2559 EN is low by default and VBUS_DUT is off.
- Program firmware through J3 only after confirming no dangerous backfeed.
- Enable TPS2559 from firmware and confirm VBUS_SWITCHED/VBUS_DUT rise.
4. Critical Signal Verification
Table
| Signal | Net Name | Expected State | Measure At | Notes |
|---|---|---|---|---|
| TPS enable | TPS_EN | LOW at reset, HIGH when port enabled | U2 EN | R18 keeps port off during reset |
| TPS fault | TPS_FAULT_N | HIGH normally, LOW on fault | U2 FAULT / U1 GPIO8 | Pull-up R3 to 3V3 |
| INA alert | INA_ALERT_N | HIGH normally, LOW on alert | U3 ALERT / U1 GPIO6 | Pull-up R19 to 3V3 |
| I2C SDA/SCL | I2C_SDA / I2C_SCL | Idle HIGH at 3.3 V | U3/DS1 pins | R4/R5 4.7 kΩ pull-ups |
| Shunt sense plus | INA_SHUNT_PLUS | Kelvin sense to R1 source side | U3 Vin+ | Must not carry 2 A current |
| Shunt sense minus | INA_SHUNT_MINUS | Kelvin sense to R1 load side | U3 Vin- | Verify polarity |
| USB service | MCU_USB_D_P/N | Only on J3 and U1 USB pins | J3 | Must not be tied to DUT D+/D- |
5. Programming and Debug Interface
Table
| Interface | Signals | Connector | Tool |
|---|---|---|---|
| RP2040 USB bootloader | J3 Pin 1 5V, Pin 2 D-, Pin 3 D+, Pin 4 GND | J3 | PlatformIO / Arduino RP2040 USB bootloader |
Procedure:
- Before connecting both USB-A analyzer path and J3 firmware cable, test for backfeed.
- Connect only J3 firmware USB.
- Verify RP2040 enumerates in bootloader or serial mode.
- Flash the firmware starter.
- Confirm serial output at 115200 baud.
6. Functional Validation
Table
| Test | Components | Input | Expected Output | Pass Criteria |
|---|---|---|---|---|
| I2C scan | U1, U3, DS1 | Firmware scan | INA226 at 0x40, OLED at 0x3C | Both devices respond |
| OLED display | DS1 | Firmware splash | Text visible | No flicker/reset |
| Port enable | U2 | Toggle OK button | VBUS_DUT off/on | EN controls OUT correctly |
| Fault detection | U2, U1 | Controlled overcurrent | TPS_FAULT_N low | Firmware logs alarm, red LED/buzzer activate |
| Current measurement 0 A | R1, U3 | No load | ~0 A | Offset recorded |
| Current measurement 0.1 A | R1, U3 | Electronic load | ~2 mV shunt | INA226 close to external meter |
| Current measurement 0.5 A | R1, U3 | Electronic load | ~10 mV shunt | Within calibration target |
| Current measurement 1.0 A | R1, U3 | Electronic load | ~20 mV shunt | Within calibration target |
| Current measurement 2.0 A | R1, U3 | Electronic load | ~40 mV shunt | No overheating/excessive drop |
| Buttons | SW1/SW2/SW3 | Press each | Serial/display event | Active-low detection works |
| LEDs | D2/D3/D4 | Firmware output | Red/green/yellow illuminate | Verify polarity; fix if reversed |
| Buzzer | BZ1/Q1 | Firmware beep | Audible beep | No excessive current |
| USB data passthrough | J1/J2/D1 | Low-risk USB device | Device enumerates | D+/D- not swapped |
7. High-Current and Protection Tests
Use a bench supply and electronic load. Do not start at 2 A.
Table
| Step | Load Current | Expected Shunt Drop | Checks |
|---|---|---|---|
| 1 | 0.1 A | 2 mV | INA226 sign, no fault |
| 2 | 0.5 A | 10 mV | VBUS drop, no heating |
| 3 | 1.0 A | 20 mV | TPS2559 and PTC temperature |
| 4 | 1.5 A | 30 mV | Stability, OLED no reset |
| 5 | 2.0 A | 40 mV | 10-minute thermal check |
Additional destructive-risk tests, only with current-limited source:
- Short VBUS_DUT to GND briefly and confirm TPS2559 limits current and FAULT asserts.
- Increase load until TPS2559 current limit triggers; confirm firmware alarm.
- Confirm PTC does not nuisance-trip during normal 2 A operation at room temperature.
- Measure temperatures of F1, U2, R1, connectors, and high-current traces.
8. USB Backfeed Tests
Table
| Scenario | Expected Result |
|---|---|
| Only J3 firmware USB connected | RP2040 powers; verify whether VBUS_PROTECTED also rises as designed |
| Only USB-A input connected | RP2040 powers from VBUS_PROTECTED; J3 should not expose unsafe backfeed to a PC |
| USB-A input and J3 both connected | Only allowed after verifying no damaging host-to-host VBUS condition |
| DUT connected while TPS_EN low | J2 VBUS remains off except leakage |
| DUT externally powered accidentally | No dangerous backfeed into J1 or firmware PC |
9. Stop Conditions
Stop immediately if any of these occur:
- 5 V appears on U1:VBAT, 3V3, GPIOs, or I2C lines.
- 3V3 is outside expected range.
- TPS2559 heats with no load.
- PTC heats with no load.
- VBUS_DUT is on while TPS_EN is low.
- FAULT is permanently active with no load.
- INA226 current sign is reversed or readings are wildly wrong.
- USB_DUT_D_P or USB_DUT_D_N is shorted to VBUS/GND.
- Firmware USB header and analyzer VBUS create unexpected backfeed.
Pass/Fail Summary
Table
| Test Section | Result | Notes |
|---|---|---|
| Visual Inspection | [ ] Pass / [ ] Fail | |
| Unpowered Continuity | [ ] Pass / [ ] Fail | |
| Power Rails | [ ] Pass / [ ] Fail | |
| Programming | [ ] Pass / [ ] Fail | |
| I2C/OLED/INA226 | [ ] Pass / [ ] Fail | |
| Port Enable/Fault | [ ] Pass / [ ] Fail | |
| Current Calibration | [ ] Pass / [ ] Fail | |
| 2 A Thermal Test | [ ] Pass / [ ] Fail | |
| USB Data Passthrough | [ ] Pass / [ ] Fail |
Board Status: [ ] Ready for use / [ ] Requires rework
Prerequisites
1. Visual Inspection
2. Unpowered Continuity Checks
3. Power Rail Verification
4. Critical Signal Verification
5. Programming and Debug Interface
6. Functional Validation
7. High-Current and Protection Tests
8. USB Backfeed Tests
9. Stop Conditions
Pass/Fail Summary
