New Industry Products

Power Integrations Debuts a New Family of Flyback Switcher ICs

September 28, 2021 by Gary Elinoff

The new family of devices feature an integral USB PD Controller and support USB PD 3.0 + PPS and QC4 protocols.

Power Integrations InnoSwitch3-PD family of ICs is aimed at USB Type-C, USB Power Delivery (PD), and USB Programmable Power Supply (PPS) adapters. The highly integrated devices employ a primary side switch based on the company’s high-voltage PowiGaN technology. It includes a USB-C and PD controller, a multi-mode quasi-resonant flyback controller, a synchronous rectification driver, and secondary-side sensing. Communication between the primary and secondary sides is achieved via the company’s FluxLink technology.

Image courtesy of Power Integrations


Because the microcontroller is integrated into the InnoSwitch3, the difficult, time-consuming task of developing the software needed to build a USB-C PD+PPS power adapter is eliminated. It also allows for a reduced BOM.


The Need

As noted by Aditya Kulkarni, senior product marketing engineer at Power Integrations: “InnoSwitch3-PD ICs target designers seeking the ultimate in charger power density. This requires the highest level of integration and maximum efficiency to limit self-heating. Our latest addition to the InnoSwitch3 family dramatically simplifies the development and manufacturing of compact, energy-efficient USB PD power supplies for smartphones, tablets, notebooks, and other devices that benefit from fast charging. InnoSwitch3-PD ICs reduce the BOM count to half that of conventional designs, reducing design time and simplifying high-volume manufacture for slim, ultra-compact OEM and aftermarket chargers.”


Inside the Innoswitch3-PD

The diagram below illustrates the new device in a generic configuration with the other elements of a charger. In simplest terms, the device is a high voltage switch and controller married to a USB-C & PD controller.


Block Diagram of the Innoswitch3-PD. Image courtesy of Power Integrations video


On the secondary side, there is also a direct drive for a synchronous rectification (SR) FET and a drive for a load switch. There is also a temperature sense unit to monitor external parts of the power charger.


The Heart of the device

The heart of the device is the Integrated USB-C & PD controller, which communicates directly with the USB-PD charging system. This allows the charger that will ultimately be built to deliver voltage in 10 mV steps and with very small steps in current.

It’s also the main reason that chargers built with the InnoSwitch3-PD feature a BOM count that, according to Power Integrations, is about half that of competitive solutions for a 60-watt USB-PD adapter.


Members of the Series

All units support USB PD 3.0 + PPS as well as QC4 protocols. They are up to 95% efficient, with no load power consumption as low as 14 mW.

The six current members of the series are listed below:


Image courtesy of datasheet


The first three devices have a power switch voltage rating of 650V, and the second three are rated at 750V.

Devices with outputs of up to 100 watts can be built without a heatsink. There is also onboard one-time programmable memory to hold customer-specified output voltage and current combinations.


Reference Designs

The DER-837 is a 45 watt USB PD 3.0 Power Supply with 3.3 V – 11 V PPS Output. It’s dimensions are 48 x 46 x 23.8. It uses 54 parts.

The RDR-838 is a  USB PD 3.0 Power Supply with a 3.3 V – 21 V device with a 60-watt output. It uses 61 parts with dimensions of 57 x 57 mm with a height of 19.21 mm.



  • The devices are available in 13.43 x 9.4 x 0.63 mm InSOP-24D packages.