Introduction to the scheme of semiconductor PD fast charging shielding absorbing materials

Mr. Gao Jianlong, the project manager of Nanxin AC-DC, gave a speech and gave an in-depth introduction to Nanxin Semiconductor's product layout in the fields of gallium nitride encapsulated chips and fast charging, with the theme of "Introduction to Nanxin Semiconductor PD Fast Charging Shielding Absorbing Material Solution".

Nanxin Semiconductor unveiled a heavyweight core product in a speech, introducing the characteristics of gallium nitride itself after the emergence of gallium nitride devices, such as fast switching speed and low losses, which have been applied in PD fast charging.

The Nanxin SC3057 adopts QFN6 * 8 packaging and uses power and signal partition routing. Simplify heat treatment through large-area PAD heat dissipation. SC3057 operates in QR and DCM modes, which is conducive to high-frequency applications and conforms to the characteristics of gallium nitride. At the same time, SC3057 has complete protection functions, supports internal and external overheating protection, and supports segmented power supply. Segmented power supply only requires a single winding, which is friendly to EMI and synchronous rectification.

Nanxin has launched a 65W DEMO for SC3057, which shows that the peripheral components of SC3057 are very streamlined, without the need for external resistive capacitive devices and drivers. The number of peripheral components is very small, simplifying the design and providing greater design space.Semiconductor PD fast chargingShielding and absorbing materials

The Nanxin SC3057 has a conversion efficiency of over 92.7% at 90V input, 20V3.25A full load output, and a conversion efficiency of over 94% at 220V input. Nanxin has made special optimizations to SC3057, which can easily pass EMI testing. And the Nanxin SC3057 exceeded 94% efficiency even after passing EMI testing.

The schematic diagram of Nan Xin SC3057 Gallium Nitride Fast Charge DEMO consists of Nan Xin SC3057 Gallium Nitride Encapsulation Chip, Nan Xin SC3503 Synchronous Rectification Control, and SC2151A Protocol Chip. DEMO has high-voltage starting, multiple primary side protection functions, segmented power supply, integrated drive, secondary synchronous rectification, etc. The detailed introduction of these features includes:

The Nanxin SC3057 integrates segmented power supply internally to meet the wide range output of USB PD. Compared to LDO, Nanxin integrates segmented power supply to improve voltage resistance. Detecting the output voltage of the auxiliary winding through the SW pin is a patented feature of Nanxin. Segmented power supply can reduce the number of peripheral components and lower the power consumption of the controller compared to other power supply methods, and only requires a single auxiliary winding for power supply. Compared to other power supply methods, it only requires an additional 0805 packaged inductor.

The Nanxin GaN driver adopts a differential driving technology route, which can eliminate the influence of current sensing resistance on the driving voltage of GaN devices and fully utilize the characteristics of GaN devices. Nanxin subtracts the voltage on the current sampling resistor from the proprietary voltage and applies it to the gate of gallium nitride. After long-term testing, the design ensures both performance and reliability.

For single port output applications above 65W, in order to meet LPS requirements, some applications require support for primary LPS, which is the primary constant current protection function. Nanxin will launch a single port version part number based on SC3057 in the future, supporting this feature.

Synchronous rectification uses the Nanxin SC3503 controller, which has dual modes and supports zero voltage flyback/ACF flyback and CCM/DCM/QR flyback modes.

The Nanxin SC3503 also supports driving clamp under zero voltage output, with a 4A pull current capability to ensure fast shutdown of synchronous rectifier tubes, automatic switching of 8V/6V driving voltage, and the industry's best shutdown transmission delay of 10ns and precise minimum conduction time.

The Nanxin SC3503 has a very flexible power supply mode, supporting high side and low side applications, and supporting multiple power extraction methods. Semiconductor PD fast chargingShielding and absorbing materialsBatch application of gallium nitride chargers and other products.