Cypress Semiconductor has just announced a suite of off-the-shelf, single-chip USB Type-C Port Controller solutions.
As I discussed in detail in my previous column, a new flavor of USB is heading our way, with initial deployments anticipated early this coming summer.
USB Type-C, as it is known, boasts a small, robust, non-polarized connector (it can be plugged in either way). The same connector will appear on both ends of a Type-C cable, and Type-C sockets will appear on every device, including as PCs, tablets, monitors, smartphones, and cameras.
The USB Type-C specification defines a sophisticated power delivery scheme that is capable of handling up to 100W, along with support for flexible new communication modes that can support up to 20 Gbps.
With regard to the 20 Gbps value, this actually requires a little clarification. The Type-C cable contains two high-speed channels, each of which has transmit and receive lanes. Each channel is theoretically rated at 10 Gbps. In duplex mode, this means 10Gbps in both directions simultaneously, which we typically think of as being a 10 Gbps link. Since there are two high-speed channels, this results in a theoretical maximum of 20 Gbps.
Having said this, each transmit and receive lane is capable of being driven in either direction. On this basis, in a non-duplex mode, it could be said that we have four lanes each capable of handling 10 Gbps, thereby giving a total bandwidth of 40 Gbps. However, there is one further qualifier; although the cable is specified to handle 10 Gbps on each high-speed lane, most folks aren’t there yet, and 5 Gbps is pretty much the state-of-the-art at the time of this writing, which means the best we can currently hope for out of a Type-C cable in full duplex mode is 10 Gbps.
When a Type-C is used to link two devices, those devices negotiate with each other to decide who is going to receive the power (and how much power is required) and who is going to supply the power (and how much power is available). Furthermore, in order to support the more sophisticated power and data modes, Type-C cables contain an electronic ID that can inform the other elements in the system as to that cable's power capacity and the data bandwidths it can handle.
Time is running out
As was previously noted, initial deployments of USB Type-C-enabled devices are anticipated for early summer 2015. The problem faced by designers is that -- currently -- no dedicated Type-C controllers exist, thereby necessitating the use of an MCU-based solution.
Unfortunately, today's general-purpose MCUs do not meet the needs of Type-C applications because they do not contain an integrated Type-C transceiver. Furthermore, many applications will actually require multiple Type-C ports.
And just to add to the fun and frivolity, the rapidly evolving USB standards make compliance and interoperability something of a challenge; for example, the USB Type-C and PD compliance test specifications are currently in flux and won’t be finalized until late 2015.
Introducing Cypress's CCG1
In order to address this issue, Cypress has launched a suite of devices based on its PSoC (programmable SoC) technology, boasting a mix of programmable analog fabric, programmable digital fabric, 32KB of Flash memory, 4KB of SRAM, and a 48MHz ARM Cortex-M0+ processor, along with general-purpose input/outputs (GPIO) and a variety of communication interfaces (I2C, SPI, UART).
Block diagram for a CCG1 USB Type-C Port Controller.
These off-the-shelf devices are known as CCG1 USB Type-C Port Controllers with PD, where CCG1 = Type-C Port Controller Generation 1, and PD = Power Delivery. The CCG1 comes pre-loaded with a firmware stack that supports up to two Type-C ports, including PD support (both provider and consumer roles and all power profiles).
CCG1s are available in a variety of packaging options so as to support a wide range of end applications. These packing options include 40-pin QFN (36 mm2), a 28-pin SSOP (75 mm2), and a 35-pin WLCSP (6.9 mm2).
CCG1 devices are available in a variety of packaging options.
For example, the 40-pin QFN is targeted toward notebook and monitor applications; the 28-pin SSOP may be found in high-end power adapters, while 35-pin WLCSPs may be used in Type-C cables as illustrated below (depending on the application, some cables may use only one CCG1, while others may feature a CCG1 at each end).
A CCG1-based USB Type-C connector.
As one small example of the capabilities of a USB Type-C-enabled system, consider the fact that the IR voltage drop over a long cable may be as much as 1V. Thus, if the negotiated power delivery is 20V at 5A (100W), the receiving device might actually see only 19V. Using Type-C's unstructured vendor defined messaging (VDM) capabilities, the receiving device might measure the voltage it's actually seeing and transmit this information back to the supplying device, which could increase the voltage it's delivering so as to ensure the fastest-possible recharge rate.
For more information on Cypress Semiconductor's CCG1, including datasheets, application notes, and demonstration kits, please visit Cypress.com/CCG1.
— Max Maxfield, Editor of All Things Fun & Interesting