USB PD-3 sink controllers optimize USB Type-C applications through increased efficiency and versatile charging options. USB-C enables faster and more secure power supply and will be mandatory for devices up to 100 W in the EU from December 2024.
Image 1: As of December 2024, in the European Union, any wired chargeable device that requires up to 100W of power must use the USB Type-C charging port that meets the USB-PD specifications. (Image: tanaonte – stock.adobe.com)
The window of opportunity for proprietary chargers is closing quickly as regional regulators move to require a common charging solution based on a cable and connector compliant with the USB Type-C standard. As of December 2024, in the European Union, any wired, chargeable device that requires up to 100W of power (laptops are temporarily exempt from the requirement until 2026) must use the USB Type-C charging port that conforms to the USB-PD specifications corresponds. Further regulations adopting this standard will come into force in India and Saudi Arabia in 2025, followed by California in 2026.
Image 2: USB Type-C alone can only deliver 5V at 3A, for a total of 15W. To achieve 100W, specifications such as USB PD 3.0 or USB PD 3.1 are required. (Image: Just Jus – stock.adobe.com)
What does USB Type-C do when it comes to power supply?
USB Type-C alone can only deliver 5V at 3A, for a total of 15W. Reaching 100W requires specifications such as USB PD 3.0 or USB PD 3.1, which ensure Type-C connectors can handle higher voltages and can simultaneously transmit data at high speed.
USB PD 3.0 supports up to 100W of power and fixed voltages of 5V, 9V, 15V and 20V at a maximum current of 5A. The updated USB PD 3.1 specification provides an extended power range (EPR ) and an Advanced Voltage Supply (AVS) that increases output power up to 240W and adds three new fixed voltages of 28V, 36V and 48V.
The USB PD 3.x specifications improve on previous PD 2.0 versions by increasing the amount of information exchanged between a sink (the device that receives power) and a source (the device that supplies power). to include factors that may affect the application, such as: B. the charging status of the device battery, the battery temperature, failures and overvoltage.
The 100W power delivered via USB PD 3.0 is enough to charge some laptops, monitors and even some TVs. USB PD also supports video and audio output, including DisplayPort and HDMI, as well as data transfer protocols such as Thunderbolt 3.
These are the advantages of the USB Type-C standard for developers and users
Product development can take advantage of USB PD 3.x to provide a better user experience with faster charging and data transfer, as well as device compatibility with a single cable and connector. You can also claim to reduce the electronic waste that consumers and companies generate by using multiple cables and chargers to charge multiple devices.
This technology allows designs to be simplified with fewer connectors and components. Additionally, manufacturing and shipping costs can be reduced by eliminating the weight and additional packaging of the chargers, and updating new device-specific chargers requires less time and effort.
By using a single cable and connector for multiple functions, development teams can focus on developing new and improved applications that take advantage of the high performance and data rate of USB Type-C PD. Additionally, they can improve the user experience and functionality of their products with additional features such as docking stations, hubs and converters that expand device connectivity and compatibility.
When developing new applications that use USB PD 3.0, development teams face several challenges, such as: B. compliance with the USB-PD specification and ensuring interoperability with other devices and chargers.
Preventing damage or injury from overvoltage, overcurrent, or reverse polarity is another critical issue, especially since solutions using this technology use more complex circuitry and firmware than previous generations. To overcome these challenges, there are power controllers that support multiple protocols and configurations, as well as evaluation boards that enable rapid prototyping and verification.
Using USB Type-C PD
A key to USB PD 3.0 is the ability to negotiate and manage power between a sink and a power source via a standardized protocol. USB PD sink controllers negotiate with a USB PD source, e.g. B. a charger to record the performance profile of a device. Compliant devices can request and deliver different voltages and currents based on needs and capabilities, dynamically adjusting power levels during operation.
The process of negotiating and managing electricity delivery consists of four phases:
- Die recognition occurs when the sink and source identify each other as USB PD compatible devices and establish a data communication channel via the configuration channel (CC) pins on the USB Type-C connector.
- At the Capacity exchange The source passes its supported power profiles (voltage and current values) to the sink, which then requests a profile that meets its requirements.
- The Performance contract is a procedure by which the source can accept or reject the sink’s request. If accepted, the source begins to deliver the requested power to the sink using the agreed performance parameters.
- Die Performance rule update allows the sink or source to initiate a new power negotiation to account for changes in the battery level or load on the sink or changes in the source’s input power.
USB PD 3.0 uses extended messages that govern the exchange of information between a sink and a source, such as: B. Battery status, temperature or manufacturer-specific data. It also supports programmable power supply mode (PPS), which allows finer control of the source output voltage and current, as well as seamless switching of power supply roles between sink and source without interrupting data communication.
Another key feature of USB PD 3.0 is reverse charging, which allows a device with a higher battery capacity to charge a device with a lower battery capacity, regardless of their role in power distribution. For example, a laptop can use the same USB Type-C cable to charge a smartphone, or the same smartphone can charge a headset, an obvious advantage for device users who can only carry a single cable to charge multiple devices.
Reverse charging may not be compatible with all devices or chargers. Additionally, the battery life of the source device may be shortened and the complexity and cost of the circuit design may increase. As with all electronic applications, development teams must weigh the disadvantages of implementing reverse charging to ensure compliance with USB PD 3.x specifications and test interoperability with a range of devices and chargers.
This is how USB 3 sink controllers work
To enable USB PD 3.x functionality in their devices, development teams can use special sink controllers that support the protocol and handle communication with the source device.
Diodes Incorporated provides highly integrated and cost-effective solutions that enable fast charging, reverse charging, PPS mode and other features of USB PD 3.x. They also support older protocols such as Qualcomm Quick Charge 4+ and Huawei FCP/SCP, ensuring compatibility with a wide range of chargers and adapters.
The AP33771 (Figure 3) is a USB PD 3.0 controller that features USB PD 3.0 compliant firmware and an interface with a pre-installed power menu, making it easier to use. It offers an output channel that can deliver up to 27W of power.
Figure 3: The AP33771 USB PD 3.0 controller has an interface with a pre-installed power menu. Its output channel delivers up to 27W of power. (Image: Diodes)
The AP33772 (Figure 4) is a USB PD 3.0 controller that uses an I²C interface and integrated firmware to negotiate current and voltage. This provides greater flexibility in implementing all PD sink functions. The device also offers two output channels that can deliver up to 45W of power and has built-in over-voltage protection (OVP) for each channel, which can prevent damage to the end device in the event of a defective charger or cable.
Figure 4: The AP33772 has an I2C interface and integrated firmware for negotiating current and voltage. (Image: Diodes)
Diodes also offers a sink controller for USB PD 3.1, the AP33771Cwhich supports EPR/AVS up to 28V and Standard Power Range (SPR)/PPS up to 21V.
Each of these controllers offers low standby power consumption, high efficiency and thermal protection features. They are available in W-QFN4040-24 package types with a small footprint (4 mm x 4 mm), making them suitable for compact and portable devices.
Diodes also offers two evaluation boards for its USB PD 3.0 controllers. The AP33771-EVB and that AP33772-EVB are both designed for charging applications with a device with a Type-C port and a PD charger or adapter with a Type-C port. The AP33771-EVB uses a simple resistance setting for USB PD negotiation, while the AP33772-EVB uses I²C.
Conclusion
USB Type-C is on its way to becoming the global standard for data connections between devices. The USB PD 3.x protocols provide the opportunity to develop applications that enable more power, faster charging and better data transfer for devices with globally accepted plugs and cables, eliminating the need for device-specific chargers. With Diodes Incorporated solutions, USB PD 3.0 or PD 3.1 can be easily integrated into devices to increase performance and improve user experience. (n/a)
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