USB Power Delivery Adapter
This page is a work in progress. Some details may be missing or incomplete.
USB Power Delivery (USB PD) is a standard for negotiating power delivery over USB-C connections. The Bus Pirate USB PD adapter is a breakout board for the AP33772S USB PD sink controller, which can be used to test and debug USB PD devices and connections using the usbpd command
The adapter includes TVS diodes for protection, level shifting for the CC lines, an output control FET, a fuse, a current sense resistor, a temperature sensor, and indicator LEDs for power and USB PD status.
Coming soon! Manufacturing will begin after Spring Festival (March 2026).
Features
- Works with the Bus Pirate I2C mode
usbpdcommand - AP33772S USB PD 3.1 Sink Controller: Manages USB PD communication and power delivery, sink only.
- Standard Power Range (SRP) and Programmable Power Supply (PPS) profiles up to 21 volts.
- Adjustable Voltage Supply (AVS) and Extended Power Range profiles up to 28 volts.
- Over/Under Voltage Protections (OVP/UVP), Over Current Protection (OCP), Over Temperature Protection (OTP)
- Moisture Detection in the USB Connector
- TVS diodes shield the USB-C port from voltage spikes and ESD events.
- Output control FET enables/disables power output.
- 30 volt/500 mA fuse to safeguard against high-ish voltage shorts.
- Current sense resistor for real-time tracking of power draw.
- Temperature sensor prevents overheating.
- Level shifting on CC0/CC1 boosts 1.1 volt signals to 5 volts for easy analysis with budget logic analyzers.
- Power and USB PD status LEDs.
AP33772S is a USB PD sink controller, which means it can only be used to test and debug devices that provide power over USB-C (USB chargers). It cannot source power to other USB devices (e.g. a phone or power bank).
Many USB power supplies can provide high voltage and current that could potentially be dangerous. We chose to use a fairly small 500mA fuse for safety. If you want to pull more current, you will need to replace or bypass the fuse. Be very careful if you choose to do this, and make sure you understand the risks of working with high voltage and current.
Status LEDs
PWR indicates that a USB power source is connected and providing power.
| State | LED Indication | VOUT | Comments |
|---|---|---|---|
| INIT | Off | OFF | VBUS/Rp attached and AP33772S initialization |
| CHARGING | 4-sec Breathing | ON | Successful negotiation or enter Non-PD Mode |
| MISMATCH | Full Light | OFF | VSELMIN mismatch (VREQ < VSELMIN) |
| MOISTURE | 2-sec Flicker | OFF | Abnormal impedance detected in the Type-C connector |
| FAULT | 0.6-sec Flicker | OFF | OVP, OCP, UVP or OTP occurs |
STAT indicates the status of the USB PD connection, according to the table above. Source: AP33772S datasheet.
CC Line Level Shifter
USB PD communicates over the CC0 and CC1 lines. The signal levels on these lines are 1.1 volts for a high and 0 volts for a low, which is not a valid range for most cheap logic analyzers.
The Bus Pirate USB PD adapter includes level shifters that bring these signals up to 3.3/5 volts, making them easier to analyze with common tools.
The shifter is based on a simple comparator set to flip at a threshold of around 0.628 volts. Output level is determined by the Bus Pirate VOUT voltage.
Pin Breakouts
USB Pins
| Pin | Description |
|---|---|
| D+ | USB D+ data line |
| D- | USB D- data line |
| SBU2 | Sideband use pin 2 |
| SBU1 | Sideband use pin 1 |
| CC2 | Configuration channel pin 2 |
| CC1 | Configuration channel pin 1 |
Header J6 breaks out the raw USB-C signals.
Other Pins
| Pin | Description |
|---|---|
| CC1 Shift | Level shifted CC1 signal |
| CC2 Shift | Level shifted CC2 signal |
| Flip | Indicates the orientation of the USB-C plug |
| VSEL | Startup voltage selection pin, set by a resistor value |
| OTP | Temperature thermistor output pin |
| GND | Ground |
Header J8 breaks out signals from the AP33772S USB PD controller, and the level shifted CC1 and CC2 signals.
Resources
Get a Bus Pirate
Get Bus Pirate & Accessories
- Browse Complete Bus Pirate hardware collection
- Bus Pirate 5 REV10 with enclosure
- Probe Cable Kit
- Auxiliary Cable Kit
- Quick Connect Adapter
Community
Documentation
Here’s some other fun stuff you might enjoy.