Laptops are equipped with more and more functions, which require high-power Power Delivery. PD is a unified power supply protocol developed by the USB Association to unify connectors through USB Type C. Ideally, as long as the device supports PD, whether it is a laptop, tablet, mobile phone or other product, it can be charged/powered by a USB Type C cable and a PD charger, and can be used to support fast charging. For laptops, a higher-performance laptop may require a 100W power supply, so through the PD protocol, the laptop can If the power supply applies for the 20V/5A profile, the power supply will provide the laptop with 20V and up to 5A power supply.

Therefore, this solution uses a 100W power adapter for USB PD3.0 Type-C applications as an example. The main controller uses Lead Trend Semiconductor LD7798 PFC+PWM Combo IC, and is paired with the secondary side synchronous rectifier LD8526GL and LD6612 to realize the high-efficiency, low no-load standby power consumption PD charger in this case for charging/power supply. This case will use LD7798+LD8526GL+LD6612. It is mainly a PFC+PWM Combo QR+SR+PD, which can greatly simplify PWM and SR peripheral components. PWM QR is suitable for applications below 100W, allowing designers to adjust it to product applications in various fields. Leadtrend Semiconductor LD7798 is a Multi-Mode PFC+PWM Combo Controller IC. It combines QR_Flyback (Quasi-Resonant_Flyback) and CCM controller in an SOP-16 package. In the QR_Flyback part, it is a valley switching operation (Valley Switching Operation). This function can effectively reduce MOSFET switching losses to improve overall efficiency. This device can minimize the number of components to save circuit space and reduce the overall material cost of the circuit.

LD7798 has high-voltage start-up, sleep mode, green mode energy-saving operation, internal slope compensation, and soft-start functions, which can reduce power loss and improve system performance. With complete protection functions such as OPP (Over Power Protection), OVP (Over Voltage Protection), OCP (Over Voltage Current Protection) and input/output low voltage protection, LD7798 can prevent circuit damage from abnormal situations during operation. In addition, LD7798 has frequency characteristic exchange and soft drive functions, which can reduce noise and improve conducted interference and radiated interference. It has built-in OSCP (output short-circuit protection), external OTP (over-temperature protection function) and SDSP (secondary diode short-circuit protection function) on the CS pin and other protection functions.

LD8526GL is a secondary-side synchronous rectification (SR) driver IC. It is suitable for flyback circuit architectures in CCM, DCM and QR modes, and can use synchronous rectification at the low-side negative output and high-side positive output positions. LD8526GL can be used for CCM and DCM operation. Under light load conditions, LD8526GL can enter a power-saving mode to reduce the operating current by stopping the SR MOSFET drive function. It can generate its own power supply voltage through the rectification application of low output voltage at the negative output or positive output position to maintain operation. There is no need to provide additional power for IC operation. It can be self-powered without the need for auxiliary windings. It can reduce the number and circuit space of many system circuit peripheral parts and control circuit components, and reduce the material cost of power supply applications. It can support applications with peak load function (the highest frequency can reach 130kHz), and is also suitable for PD applications. The output voltage range is 3V to 21V, and the IC shutdown level can be set programmably.

LD6612 is a USB Power Delivery (USB PD) Type-C controller on the secondary side, enabling efficient, slim form factor offline AC-DC designs. The 8-bit MCU is embedded to handle the PD protocol, policy engine and device policy manager with built-in Biphase Marker Coding (BMC) for USB PD communication or other proprietary protocols (e.g. QC2.0/QC3.0). To minimize external components, it integrates a shunt regulator, voltage and current monitoring and control circuit blocking N-MOSFETs. The built-in voltage regulator provides a 4.8V MCU and peripherals operating range from 3.3 to 24V on a single supply.

▶Scenario application diagram

▶Product entity diagram

▶Development board photos

▶Scheme diagram

Core technology advantages

• IC includes QR_Flyback and CCM multi-mode controller

• Integrate PFC boost and QR flyback controller, internal soft-start function and PFC on/off control

• Brown in/out protection and X-cap discharge function

• Adjustable OTP (over temperature protection) SDSP (secondary diode short circuit protection function)

• SR low output voltage and/or high-side rectified operation is self-powered and requires no auxiliary winding

• 150V VIN maximum rating for wide VOUT range applications

• Programmable shutdown level, OCP (cycle-by-cycle current limit)

• Smart and stable system, high efficiency and stable USB-PD application, OVP (over voltage protection)

• Embedded MCU with 16kbyte OTP and 256+384bytes SRAM

• Programmable output line loss compensation function, internal OTP function and external locking protection

Project specifications

• Full voltage input range: 90Vac ~ 264Vac

• Maximum output power: (20V/5A) 100W

• Output voltage range: 5A/3A, 9V/3A, 15V/3A, 20V/5A

• Four-point average efficiency > 88% @(25%, 50%, 75%,100%)Efficiency Meet CoC Tier 2

• No-load standby power consumption is less than 75mW, EMI meets EN55032 Class B

• With complete protection functions such as OCP/OVP/OTP/OPP/OSCP

• Suitable for CCM, DCM and QR modes

• Suitable for applications with peak load function (maximum frequency 130kHz)

• Display board PCB size LxWxH=93mm x 47mm x 22mm

• USB PD2.0 and PD3.0 (PPS) and other proprietary protocols such as QC2.0, QC3.0, QC4.0, PPS