USB Power Delivery, or PD, is a protocol that starts a digital negotiation between a charger and whatever it is plugged into. The moment the cable connects, both sides exchange messages about what voltage and current they support, then settle on a power level both can handle safely.
This negotiation is why the same charger can deliver 20W to a phone, 45W to a tablet, and 100W to a laptop. Rather than sending a fixed voltage, this device-aware flexibility is the core feature that separates PD from older charging systems.
PD 3.0 introduced PPS, or Programmable Power Supply, which allows voltage to be fine-tuned continuously rather than jumping between fixed steps. This is exactly what powers fast-charging systems from brands like Samsung, letting them adjust charging speed more precisely based on how full the battery already is.
PD 3.1 brought Extended Power Range (EPR), pushing the maximum from 100W up to 240W, which means USB-C can now power most laptops and even some monitors.
Charjett's PD-compliant chargers and cables fully support this negotiation process, so whatever device gets plugged in ends up charging safely and at its optimal speed.