No one will dispute the utility of the USB interface for transmitting data and handling limited charging functionality. But there’s still a USB-related spec that’s flying under the radar despite its high ceiling when it comes to usefulness. I’m referring to the USB Power Delivery specification, or USB PD.

The USB PD spec expands the power delivery mechanism of the USB interface by providing up to 100 W and data over the same single cable. Another enhancement is bidirectional power, meaning that either the host or the peripheral can act as the power source. Previously, only a host was able to provide power, so USB PD's power sharing abilities have significant implications on the battery life of a range of systems.

It's also important to note that the new spec maintains backwards compatibility, so older devices will be able to interface without a hitch.

Power ON

To help further the USB PD spec, ON Semiconductor introduced a solution for high-density power adapters for notebooks, tablets, and other portable devices. It comprises the NCP1568 active clamp flyback (ACF) controller and a corresponding high-speed, half-bridge driver, the NCP51530. This results in a 65 W USB PD-compliant adapter with a 30 W/in.³ power density that operates at 94.5 percent peak efficiency.

The NCP1568 is a highly-integrated AC-DC PWM controller in an ACF topology, including zero voltage switching (ZVS) for applications up to 1 MHz. Furthermore, the NCP1568 controller can implement the ACF topology with proven super-junction FETs or Gallium-Nitride (GaN) FETs.

Housed in a small TSSOP-16 package, the NCP1568 includes various protection features. The quiet skip feature eliminates audible noise during operation, which is an essential requirement for indoor power adapter applications.

The NCP51530A/B are 700 V high-frequency, high- and low-side drivers for directly driving two N-channel power MOSFETs. A particular feature is the fast dynamic response – a 30 ns propagation delay is ideal for high-frequency operation, while 5 ns delay matching ensures the highest level of efficiency.

The device provides a robust solution with high dv/dt immunity (up to 50 V/ns) and negative transient immunity. It’s available in an SOIC-8 or DFN-10 package, with the latter offering improved creepage distances and an exposed pad. An AEC-Q100-qualified version is available in an SO-8 package for automotive applications.

Both parts are sampling now and will be in full production sometime in the second quarter.

For more information on what ON Semiconductor is doing around USB and power deliver, visit their USB-C and Power Delivery Solutions webpage.

eletter-03-27-2018