USB
What is USB?
Definition
Universal Serial Bus (USB) is a standard port that enables you to connect external devices (such as digital cameras, scanners, keyboards, and mice) to computers.
USB OTG
USB On-The-Go (OTG) allows two USB devices to talk to each other without requiring the services of a personal computer (PC).
USB to USB OTG converters are used in conjunction with application-specific integrated circuits (ASICs) or microprocessor-controlled application-specific standard products (ASSPs) that already support USB but need to add VBUS control and the extra signaling required to become USB OTG compliant.
USB OTG retains the standard USB host/peripheral model in which a single host talks to USB peripherals. OTG does introduce, however, the dual-role device (DRD) that is capable of functioning as either host or peripheral. A host and peripheral can exchange roles if necessary.
USB-C
USB Type-C cable and connector specification simplifies the way we interconnect and power devices, and is increasingly becoming the preferred universal standard.
USB-C allows for bidirectional power. A peripheral device can be charged, and the same device can also supply power to the host device. USB-C specification requires a device to negotiate to be either a power provider (source) or a power user (sink) before power transfer takes place. The connectors at both ends of a Type-C cable are identical, allowing for reversible plug-in. Each connector is also flippable, allowing it to be plugged in without worrying about polarity.
USB-C is used in applications such as smartphones, tablets, laptops, point-of-sale terminals, digital cameras, handheld computers, and portable printers, as well as in other portable medical, industrial, and automotive equipment.
USB PD
The USB Power Delivery (USB PD) specification allows for faster and more flexible power delivery. While USB-C describes the physical connector, USB PD is a charging protocol. USB PD can provide up to 240W from the same USB Type-C connector.
With USB PD, the power source (such as a wall adapter) and the in-line device (such as a cell phone) communicate their power capabilities and power needs, respectively, in proper voltage and current levels before the source provides power over the USB cable. USB PD poses new power requirement challenges because of the variety of voltage and current combinations available to supply the wide range of power the USB PD standard can provide.
USB ICs
Thanks to USB-C and USB PD, compact electronic devices can now be fed by a small, single, bidirectional cable that delivers data, video, and power. Although USB-C and USB PD are making electronic devices easier to manage for end users, complying with the protocol can involve multiple hardware components, complex software, as well as custom firmware development.
ICs for USB-C and USB PD designs provide the high levels of integration and flexibility needed to create compact, power-efficient electronics compatible with bidirectional data and power delivery requirements. These can include chargers, converters, and controllers, as well as power path and protection devices.