Introducing USB PD 3.0, enabling fast charging of USB Type-C batteries and power supply system for all-in-one PCs

The latest version 3.0 of the USB Powered (USB PD) standard introduced by the USB Developers Alliance (UBS-IF) will enable power adapters, mobile power and charger manufacturers to develop new products for new consumer devices such as laptops, tablets and mobile phones. wave. The USB PD 3.0 via USB Type-C connector can be used to increase the power rating of the USB interface from 7.5 watts to a maximum of 100 watts using a maximum of 20 volts / 5 amps. With the introduction of USB PD 3.0, it is possible to quickly charge the battery through the USB Type-C and to provide a power supply system for the all-in-one PC .

With the introduction of the USB Type-C interface standard, the new USB PD 3.0 standard will be recognized. USB   The Type-C standard provides a new connector/socket design. This USB-C plug can be plugged in two directions for user convenience. Compared to the familiar USB Type-A connector, this USB-C connector is smaller and can carry HDMI, DisplayPort communication and USB communication (see Figure 1).

Crucially, the USB-C connector is also compatible with USB PD 3.0. As a result, power adapter manufacturers can now produce power supplies or chargers that can deliver up to 100 watts of power through a small two-way connector in a standard form factor and protocol. This means that consumers will soon become familiar with and understand the technology, which also allows any USB-C device to interoperate.

This seems to be a good idea. In fact, analysts also believe that in the period 2016-2021, the key controller components market adoption of USB-C interface USB PD devices will achieve 89 percent compound annual growth rate.

Figure 1: The standard USB-C interface can replace multiple other interfaces in consumer devices

However, producing a power device that is compact, competitive in material cost, and has all of the above advantages is more challenging than system designers can imagine.

First, we can foresee that the USB-C and USB PD standards will ensure interoperability between different manufacturers' products, helping to maintain consumer confidence in the USB interface as a charging and powering channel for multiple devices. In fact, both the USB standard itself and the standards that coexist with UBS (such as Qualcomm® QuickChargeTM technology for mobile device Quick Charge) require regular revisions and updates to take into account emerging user needs and new technology features. The latest version of Quick Charge technology is version 4.0. This means that three major changes have been made since the v1.0 release, and the 4.0 version is unlikely to be the last.

At the same time, the USB PD 3.0 standard itself is more than just a power supply specification that sets the input voltage and current limits of the consumer. Its role is more about the communication protocol, through which the connected devices can establish their own identity. Execution functions and the roles that need to be played as a power or power source in any given scenario. The standard also includes programmable power supply regulations that can produce variable output power for a variety of end devices . of.

In summary, engineers responsible for designing USB-C power adapters or chargers with USB PD 3.0 capabilities typically require:

Meet the USB PD 3.0 specification requirements

Provide periodic updates in the design to account for specification changes

Provides ideal features such as programmable power supplies and support for Quick Charge technology

Disadvantages of discrete implementation

A USB-C PD3.0 system that meets the above requirements has certain functional requirements, some of which will be implemented by hardware and software, respectively.

Hardware features include:

USB PD power controller

Voltage regulator to power the power controller and other active components

a high pressure P   -   MOSFET, which supplies power to the powered device based on the pulse width modulation signal from the USB PD power controller

High voltage gate driver driving the MOSFET

Short circuit protection on the configuration channel (CC) specified in the USB-C standard. The CC bus is used to transmit PD protocol signals.

Overcurrent protection on the input power bus (V BUS )

Electrostatic discharge protection

In software, the power adapter needs to implement the USB-C and USB PD3.0 protocols and is compatible with the Quick Charge protocol when necessary.

The above hardware and software functions can be implemented by using multiple discrete components: usually through a microcontroller to perform system control and power control functions and running protocol software, in addition to discrete MOSFETs, gate drivers, and overcurrent, overvoltage, and static Discharge protection component.

In this way, by using a plurality of discrete components to implement a USB-C power adapter, the mobile power source or charger has the following disadvantages:

Need a lot of components

The large footprint of multiple components on the board makes P CB larger, more complex and more expensive

A system of multiple fixed-function hardware components is not flexible, making it more difficult to quickly update designs based on changes in specifications or user requirements

Integrated for simplicity and cost reduction

In order to avoid these defects, Cypress Semiconductor introduced the CCG3PA high integrated power transmission controller for USB-C in the first half of 2017. In CCG3PA, in addition to the high voltage power switch, other hardware functions are integrated into one chip system.   Cypress USB-C, USB PD 3.0 Quick Charge 4.0 and protocol stack, and the software running on the processor core with ARM®Cortex®-M0 64kB flash memory is read and written simultaneously functions, thus facilitating more Apply firmware upgrades to maintain interoperability.   CCG3PA is certified to meet the USB PD 3.0 standard at the factory. The chip also passes Quick Charge   4.0, 3.0 and 2.0 certification.

As shown in Figure 2, CCG3PA is highly integrated, with fewer components, smaller board footprint, simpler board layout, and material cost and PCB compared to functional equivalent systems implemented using discrete components. The advantage of lower cost.

Figure 2: How does the CCG3PA power controller implement BoM integration?

These system-level advantages for the entire product lifecycle are important, but there is one more important point in the design cycle: CCG3PA is supported by a complete set of development resources that can be significantly larger than the average development process using discrete components. Shorten time to market. These resources include:

Independent reference design for a 45W USB-C notebook power adapter and a mobile device charger with a maximum power of 27W. Both reference designs have files containing schematics.

A comprehensive CCG3PA evaluation kit (part number CY4532) that includes a USB-C powered or charging port and a USB Type-A charging port. The evaluation kit can be used to power and charge laptops, mobile phones and other USB devices and to charge single or dual battery USB-C mobile power.

Together, these reference designs and evaluation boards provide an advanced blueprint for many end product designs that can be tailored to meet specific customer needs with minor modifications.

in conclusion

The CCG3PA is available in a 24-pin QFN or 16-lead SOIC package and is suitable for USB PD 3.0 compliance.   The compact system-on-chip on the standard USB-C simply adds an external MOSFET and AC-DC converter to become a complete offline power adapter/charger that meets the latest U SB power supply standards.

CCG3PA adapter and charger integrated solution provides programmable power supply for multiple terminal devices and supports Qualcomm   Quick   Charge charging technology. Development time, BoM cost and space can be saved compared to any technology that uses discrete components.