Understanding USB PD(Power Delivery) and QC (Qualcomm Quick Charge)

Fast charging technologies have revolutionized how we power our devices. Two leading standards, USB Power Delivery (PD) and Qualcomm Quick Charge (QC), have been at the forefront of this revolution. In this post, we’ll explore the technical specifics of these protocols, focusing on their evolution and capabilities in terms of voltage and current.

USB Power Delivery (PD)

What is USB PD?

USB Power Delivery is a versatile fast-charging protocol that caters to a wide range of devices, offering higher power and flexibility, especially with the introduction of USB-C.

Evolution of PD: PD 2.0 to PD 3.1

  1. PD 2.0:
    • Voltage Range: Up to 20V
    • Maximum Current: Up to 5A
    • Power Delivery: Up to 100W (20V x 5A)
  2. PD 3.0:
    • Introduced Programmable Power Supply (PPS) for fine-grained control over voltage and current.
    • Retained the same voltage and power specifications as PD 2.0.
  3. PD 3.1:
    • Extended Power Range (EPR): Introduced with PD 3.1, increasing the maximum voltage.
    • Voltage Range in EPR: Up to 48V
    • Maximum Current: Up to 5A
    • Power Delivery in EPR: Up to 240W (48V x 5A)

Key Features of USB PD

  • Dynamic Power Management: Allows devices to negotiate power levels for optimal charging.
  • Broader Compatibility: Supports a wide range of devices beyond smartphones, including laptops and tablets.

Qualcomm Quick Charge (QC)

Overview of QC

Qualcomm Quick Charge (QC) is a fast-charging technology developed by Qualcomm Technologies Inc. QC is designed to work with any device with a Qualcomm Snapdragon processor. QC technology delivers more power compared to a standard USB connector that charges most mobile devices.

QC charging technology elevates the voltage of a charge while avoiding overheating the USB cable. Quick Charge 5 can deliver more than 100 watts of power to its users and has numerous essential safety features to protect your devices from overheating, over-voltage, or over-current. While QC works well with devices with a Qualcomm Snapdragon chip, it is not limited to Qualcomm devices. Any manufacturer can license QC technology from the company, which is common in many Androids, tablets, power banks, and chargers.

Versions and Their Technical Specifications

  1. Quick Charge 1.0 (2013): First introduced in 2013, it was capable of charging devices 40% faster than older technologies, often achieving a full charge in under three hours. It was widely used in first-generation smartphones like the Moto X.
  2. Quick Charge 2.0 (2014): This version was scalable and connector-independent, supporting USB Type-A, micro, Type-C, and various proprietary connectors. It offered up to 24 watts with a micro USB connector, 36 watts with a Type-C connector, and 60 watts or more for higher classes.
  3. Quick Charge 3.0 (2015): Marking a significant improvement, QC 3.0 charged devices four times faster than traditional methods and twice as fast as QC 1.0. It was 38% more efficient than QC 2.0 and supported a broader range of voltages and connectors.
  4. Quick Charge 5.0: This latest version surpasses previous iterations by providing over 100 watts of power. It includes safety features to protect against overheating, over-voltage, and over-current.

Each version of Qualcomm Quick Charge has brought significant advancements in charging speeds and efficiency, reflecting the evolution of smartphone charging technology.

Comparing PD and QC

USB PD, with its high power delivery and compatibility with USB-C, offers versatility for a wide array of devices. In contrast, Qualcomm’s Quick Charge provides optimized and efficient fast charging specifically for Qualcomm-equipped devices. The variable voltage feature in QC 3.0 and above ensures efficient power transfer, but it doesn’t reach the higher power capabilities of USB PD, especially with the advent of PD 3.1.


Both USB Power Delivery and Qualcomm Quick Charge have played pivotal roles in advancing fast charging technologies. USB PD’s evolution from PD 2.0 to PD 3.1 highlights its scalability and suitability for high-power applications, while QC’s focus on efficient, device-specific charging continues to benefit Qualcomm-powered devices. As these technologies continue to evolve, we can anticipate even faster and more efficient charging solutions in the future.