A
diverse array of portable devices — wireless speakers, drone cameras, VR
headsets, and motorized medical devices — is counting on the simplicity of USB
Type-C connectors to reinvigorate the charging and transfer of multimedia data
streams.

The
USB Type-C interface, which specifies reversible plug orientation and cable
direction, simplifies attaching and powering a wide range of battery-powered
devices. And it consolidates support for a broad range of interface
technologies, including DisplayPort, HDMI, and Thunderbolt (Fig. 1).

0218_Trends_Cypress_Fig-1

Fig. 1: USB Type-C is quickly becoming a gateway for connecting a multitude of devices with different power supply requirements. Image source: Cypress Semiconductor.

USB
Type-C and power delivery standards are gaining rapid support while catering to
power-source applications such as AC adapters and power supplies, power hubs,
docking stations, smart plugs, and displays. But behind this slim and sleek
connector world lies complex interface electronics battling with issues like
power delivery negotiations, built-in protections, power-sharing algorithms,
and so on.

In
this article, we take a closer look at how the USB Type-C ecosystem is quickly
evolving and how a new breed of power and interface chips is facilitating the
transition from USB Type-A, USB Type-B, and USB Micro-B devices. It especially
delves into single-chip solutions that promise to lower component count and
shrink board real-estate.

Managing power sources
Chipmakers,
for instance, are adding intelligent battery algorithms to enable smaller form
factors and faster battery charging alongside a new generation of bidirectional
voltage regulators that accept input power from a wide range of DC power
sources: AC/DC power adapters, travel adapters, and power banks.

The
chips convert a broad array of DC power sources to a regulated voltage at the
power adapter input. Intersil’s new buck-boost voltage regulator is a case in
point: It supports the USB Type-C ecosystem with buck mode, boost mode, and
buck-boost mode, providing ample flexibility for multiple ports and input
sources.

The
single-chip ISL95338 solution replaces two voltage converters currently used
for the bidirectional buck and boost modes and reduces the BOM cost of a USB
Type-C design by 50%. It employs Intersil’s R3 modulation technology to deliver
light-load efficiency and ultra-fast transient response.

0218_Trends_Cypress_Fig-2

Fig. 2: USB Type-C is becoming a universal adapter for data transport and power supply for a wide array of devices. Image source: Texas Instruments.

Next,
Texas Instruments has added intelligence to its battery charging controllers
via maximum power point tracking technology. Its battery algorithm
automatically detects the full capacity of input power to optimize current.
That allows battery charge controllers to support wide input and output voltage
ranges and more compact adapter designs.

The
controller chip also helps maintain a consistent system and charging current to
ensure the utilization of maximum input power. TI’s buck-boost battery charge
controllers for one- to four-cell (1S to 4S) designs — bq25703A and bq25700A —
promise seamless transition between different modes in the buck and boost
operation without any dead zone.

The
Dallas, Texas-based chipmaker is targeting these charge controllers for USB
Type-C ports in devices such as notebooks, tablets, power banks, drones, and
smart home applications.

The BOM savings
The
USB Type-C products — powered by two-series battery packs — require multiple
discrete components. And it adds to BOM costs and introduces additional points
of failure within the circuit. Maxim Integrated claims to have eliminated the
patchwork of chips by integrating a charger detector, boost/buck converter, and
Li-ion battery charger with a smart power selector on a single chip.

The
new chip for USB Type-C designs streamlines the charger architecture by drawing
the maximum current that the charging adapter can supply while facilitating
28-V overvoltage protection. The MAX14748 chip enables USB Type-C charging at
twice the power of Micro-USB solutions.

Meanwhile,
Silicon Labs has released a reference design to simplify the development of USB
Type-C rechargeable lithium-ion battery packs. The design solution includes a
development board, USB Type-C power delivery (PD) stack, example code,
schematics, and a hardware manual.

0218_Trends_Cypress_Fig-3

Fig. 3: A View of the USB Type-C battery pack reference design. Image source: Silicon Labs.

The
reference design (Fig. 3) is aimed at providing developers with complete
control over the battery application for negotiating a variety of power
schemes. The PD stack, for example, enables designers to create high-level
function calls in order to negotiate and convey USB Type-C messages to send or
receive power.

USB Type-C ecosystem
The
designs built around USB Type-C connectors and ports are going to require a lot
of chipsets in 2018. And the key challenges are likely to be centered around
cost, PCB size, and power management.

The
USB Type-C ecosystem also demands a new set of debugging and test tools. Take
MIPI Alliance, which has recently updated its Narrow Interface for Debug and
Test (NIDnT) specification to accommodate USB Type-C technology.

USB Type-C is the interface technology of choice
for multi-cell battery-operated devices such as smartphones, laptops, tablets,
drones, and home automation appliances. So expect a lot more action in 2018,
very likely the year of transition toward USB Type-C cables and connectors.