Protocol revisions rarely change the shape of a charger, but they change what it must negotiate. PD 3.2 adds an adjustable-voltage profile in the standard power range, and that addition has consequences for the control loop, the thermal envelope and the test evidence a buyer should expect.

This article explains what the revision adds, how the profiles relate to each other, and what a product team should put in a specification.

Is USB PD 3.2 the same as USB-C?

No; it is a power protocol.

USB-C describes the connector, while USB Power Delivery describes the negotiation that happens over it, and PD 3.2 is a revision of that protocol rather than a new cable type.

The connector specification and the power protocol are separate: a USB-C port can carry several protocols, and Power Delivery is the one that allows a charger and a device to agree on voltage and current (USB-IF: USB Power Delivery). A revision such as 3.2 changes the profile definitions and the requirements a compliant product must meet.

For a buyer, that means a product’s connector alone says nothing about its capability. The specification has to state which revisions and profiles the charger implements.

SPR AVS: adjustable voltage in the standard range

The notable addition in this revision is an adjustable-voltage supply mode within the standard power range, which allows a device to request a voltage rather than selecting from a short list of fixed steps. The purpose is similar to PPS in fixed-range applications: finer control means less conversion loss inside the device.

For charger design, implementing an adjustable profile is a control-loop task rather than a labelling task. The output has to follow the request without oscillation, hold regulation across the range, and stay inside the thermal budget while doing so.

How AVS sits next to PPS and EPR

Three profile families now coexist. PPS provides adjustable voltage for devices that use it, commonly Android handsets; EPR extends the range upwards for high-power laptops; and the newer adjustable mode in the standard range adds a further option for devices designed around this revision.

Controller and firmware implications

A protocol revision is implemented in firmware and verified on the bench. The work items are the profile advertisement, the transition behaviour between profiles, the response to a device that changes its request mid-charge, and the thermal policy that governs how long a high output can be sustained.

Buyers should ask which controller family is used and whether the firmware is fixed or field-updatable, because that determines whether a future revision is a firmware task or a new product. Component vendors publish the capabilities of their controllers and switching devices, which is the practical way to assess a proposed design (Texas Instruments: controller documentation).

Safety and protection behaviour

Higher capability increases the importance of protection behaviour: over-voltage, over-current, over-temperature and short-circuit protection are the mechanisms that keep a fault inside the charger rather than passing it to the device. WECENT specifies these protections across its platforms and verifies them through functional testing, hi-pot pressure testing and load aging, with per-batch records from the quality control gates.

Efficiency requirements for the adapter itself are set separately by market rules (Regulation (EU) 2019/1782 and 10 CFR Part 430), and EMC compliance follows frameworks such as the FCC Part 15 rules in the United States (47 CFR Part 15).

Test and certification evidence to request

Three documents answer most questions about a protocol claim. The first is a profile list showing what the charger advertises. The second is a bench record showing the output following a requested voltage, including the transition. The third is a thermal record at the sustained rating.

Where a product claims compliance rather than capability, the relevant certificate or test report should name the model and the revision tested, because a claim attached to a product family rather than to a model is not verifiable against a shipment.

Device support today and realistic timelines

Device support for a new revision arrives over product cycles rather than at once, and backward compatibility means an older device still charges on a newer charger at the rate it can accept. That is why a charger line should support the profiles its target devices use, and treat newer profiles as headroom for the next generation.

For a roadmap, the sensible sequence is to confirm the profile support in the controller, validate the control behaviour, and then make a claim only for the devices tested.

Planning a lineup that will not date

A platform that supports fixed profiles, PPS where required and the newer adjustable mode covers the widest range of devices without a redesign, provided the thermal design has headroom for the higher tiers. Keeping the mechanical platform and the plug matrix stable means a protocol update is a firmware and validation project rather than a tooling one.

WECENT produces GaN platforms across 20W–240W in the WEG series, WEP series and WET series ranges, quotes from a written specification through its OEM/ODM programme, and starts at 200 pcs per model for a pilot, with sampling, certification planning and batch traceability included.