ON Semiconductor collaborating with Weltrend to offer a fullrange of USB PD wall charger reference designs

In response to the current market demands and the latest USB standard, a leading power chip supplier ON Semiconductor has joined forces with a leader in USB Power Delivery (PD) controller Weltrend Semiconductor to offer a comprehensive range of USB PDwall charger reference designs, including a 45 W USB PD 3.0 power adapter solution with USB Type-C PD 3.0 interface and supporting Qualcomm Quick Charge 3.0 Class A protocol.

Introduction to USB Type-C, USB PD, and QC 3.0

USB Type-C is the new generation in the specification for Universal Serial Bus connectors, ports and cables, allowing bi-directional power. This means either end of a cable or connector will work when making a connection. Overall, USB type-C provides higher power charging and higher data transfer rate of up to 10 Gbps, making it increasingly popular for portable applications.

USB PD or USB Power Delivery specification, supports data communication and up to 100 W of power delivery. It defaults to support 5 V@3Aat start up, and can be modified to support 27 W, 45 W, 60 W and 100 W depending on requirements.It also supports additional options for power and voltage.USB PD 3.0 is the latest specification of the USB Implementers Forum (USB-IF) to unify the programmable power supply (PPS) for quick charging technical specification. The output voltage of USB PD3.0 extends from 5 V to the range of 3 V to 21 V, with 20 mV of step modulated voltage.

QC 3.0 is Qualcomm Technologies, Inc., a subsidiary of Qualcomm Incorporated’s, third generation of fast charging technology, with the VBUS ranging from 3.6 V to 12 V for Class A, and 3.6 V to 20 V for Class B.QC 3.0 is equivalent to QC 2.0 in discrete mode, which selects VBUS through the static D+/D- value by three-level logic of 0 V, 0.6 V, 3.3 V.In continuous mode, the new QC 3.0 provides voltage flexibility to achieve the ideal charging efficiency for portable devices by increasing or decreasing VBUS in 200 mV of small amplitude. Its maximum load current is limited to 3 A, and the maximum power up to 60 W. Qualcomm’s fast charging technology has now evolved to the fourth generation (QC4), with 20mV of step modulated voltage, while supporting USB PD. 

45 W USB PD 3.0 power adapter solution;  compact, energy- efficient design

45W USB PD 3.0 power adapter solutionfrom ON Semiconductor and Weltrend meets PD 3.0 specifications of 5V/3A, 9V/3A, 12V/3A, 15V3A, 20V/2.25A, and QC 3.0 Class A specifications of3.6 V/3 A to 12 V/3 A, with 45 W of rated output power and more than 90% of average energy efficiency. It consumes less than 30 mWin standby powermode, complying with the latest energy efficiency standards.Also, it features small footprint of only 57mmx36mmx19mm and high power density of up to 1.15W/cm3. In addition, this solution integrates comprehensive protection mechanism including adaptive output overvoltage protection, undervoltage protection, overcurrent protection, short-circuit protection, cable voltage drop compensation, open loop protection, enabling high energy efficiency and power density while ensuring high reliability. The solution offers engineers ease and flexibility in designing power adapters supporting PD 3.0 or QC 3.0 with high efficiency, power density and reliability for applications including smartphones, tablets and notebooks.

This design mainly features ON Semiconductor’s primary side high frequency quasi resonant flyback PWM controller the NCP1340, secondary side synchronous rectifier controller the NCP4306, synchronous FET the NTMFS6B03 and switch FET the ATP104, and Weltrend’s PD3.0 protocol controller the WT6632F/WT6615F. Please refer to Figure 1 for its block diagram.

45 W USB PD3.0 power adapter solution
Figure 1: Block diagram of 45 W USB PD3.0 power adapter solution

A design architecture combining quasi resonant flyback with synchronous rectifier is conducive to achieving high power density and efficiency. In this solution, ON Semiconductor’s NCP1340 uses quasi resonant current control mode, with an operating frequency of up to 150 KHz. The NCP1340 integrates X capacitance discharge capability and the new generation quiet-skip mode, featuring valley−lockout switching operation mechanism to avoid audible noise caused by unstable valley switching. This device coupled with synchronous rectifier controller the NCP4306 reduce the conduction losses of rectifier diodes through ultrafast shutdown trigger, very short conduction delay and strong driving capability. The conduction resistance of synchronous FET the NTMFS6B03 is as low as 4.8 mΩ, minimizing the conduction loss, while low gate charge and capacitance also minimizes the driving loss. The output FET isa single P-channel ATPAK power MOSFET the ATP104,featuring low on-resistance, high current, slim package and 4.5 V of driver capability.

Weltrend’s USB PD controller the WT6632F/WT6615F supporting USB PD 3.0 specification and QC 3.0 is designed for USB Type-C Downstream Facing Port (source) charging applications.It minimizes external component count by integrating USB PD baseband PHY, Type-C detection, shunt regulator, voltage and current monitoring, load switching MOSFET controller, and an 8-bit MCU to enable a small form factor and low BOM cost. It supports wide operation voltage ranging from 3 V to 30 V without the need of an external LDO. A Multi-Time-Programmable (MTP) ROM is provided for program code and user configuration data.

Figure 2: A schematic of 45 W USB PD3.0 power adapter solution

The switching frequency of this solution can be as high as up to 130 KHz at 230 Vac and full load conditions.

Energy efficiency and performance testing

We tested the 45 W USB PD3.0 power adapter solution at 90 Vac, 115 Vac, 230 Vac and 264 Vac its test results indicated a low standby power of below 27 mW at 5 V output (cable unplug) at all conditions. And at 115 Vac and 230 Vac on its evaluation board, the average energy efficiency is more than 90% at 20 V /2.25 A.

Energy efficiency test curve
Figure 3: Energy efficiency test curve

MOSFET quickly switch off while unplugging cable, and quickly switch on at Vbus dropping to 5v while plugging cable again. In addition, under all of the above conditions, the ripple and noise are tested less than 100 mV, with excellent dynamic performance and thermal performance.

Thermal Image at 20V2.25A
Figure 4: Thermal Image at 20V2.25A

There are also other proven high energy efficiency solutions jointly developed by Fairchild (now acquired by ON Semiconductor)and Weltrend are also offered to customers, together with corresponding evaluation board and user guide:

  • 24 W USB PD 2.0 power adapter solution featuring output voltages of5 V, 9 V and 12 V uses an  off-line quasi resonant PWM controller the FAN602MX, a secondary side synchronous rectifier controller the FAN6240M6X, and Weltrend’s USB PD controller the WT6630P.
  • 25 W power adapter solution supporting USB PD3.0 with PPS featuring 5 V and 9 V output voltages uses an off-line quasi resonant PWM controller the FAN604HMX, a PD secondary side synchronous rectifier controller the FAN6240M6X, and Weltrend’s USB PD controller the WT6615F.
  • 65 W power adapter solutions supporting USB PD 3.0 and QC 3.0 uses an off-line quasi resonant PWM controller the FAN604HMX, a secondary side synchronous rectifier controller the FAN6240M6X, and Weltrend’s USB PD controller the WT6632F/WT6615F.


USB Type-C interface and USB PD protocol are becoming the mainstream fast charging technology in the market. ON Semiconductor gathers its expertise in power semiconductors and Weltrend’s leading technology in USB PD to jointly launch a full range of USB PD wall charger reference designs to meet market demands. Among these designs, the 45 W USB PD3.0 power adapter solution supports USB Type-C PD 3.0 and QC 3.0 protocols, with high operating frequency of up to 150KHz, high power density of up to 1.15 W/cm3, and low standby power of 30 mW, perfectly matching all energy efficiency standards, and providing an average high efficiency of up to 90%. Coupled with Its excellent ripple and dynamic performance this reference design enables designers to quickly design compact and high efficiency power adapter supporting USB PD 3.0 and QC 3.0 for smartphone, tablet and notebook applications. Moreover, this solution’s output voltage can easily be extended to 60W.