Xinjiawei 20W PD fast charging with built-in Chengxin Micro CX7509+CX7538 overall solution! Free DEMO board application, sample application.

The Xinjiawei 20W PD fast charging charger adopts the overall solution of CX7509+CX7538, providing a 20W PD solution with a highly integrated and ultra streamlined peripheral 20W fast charging design. This charger is compact and exquisite, with a "small block" design, making it easy to go out and carry with your pocket.

Xinjiawei 20W PD fast charging supports multiple mainstream fast charging protocols, and supports 20W fast charging in two voltage ranges of 9V2.22A and 12V1.67A, which can well meet the daily fast charging needs of iPhone 12 series phones.

Xinjiawei 20W PD charger parameters:

Model: AC32

Input: 100-240V~50/60Hz 0.3A

Output: 5V3A, 9V2.22A, 12V1.67A

Manufacturer: Shenzhen Xinjiawei Technology Co., Ltd

The charger has passed CCC and RoHS certification.

Xinjiawei 20W PD fast charging adopts CX7509+CX7538

Using ChargerLAB POWER-Z KT002, it was tested that the USB-C port supports Apple 2.4A, Samsung 5V2A DCP protocols, as well as QC2.0/3.0, AFC, FCP, PD3.0, and PPS fast charging protocols.

At the same time, it also has three fixed voltage ranges of 5V3A, 9V.22A, and 12V1.67A, as well as two PPS voltage ranges of 3.3-5.9V3A and 3.3-11V1.8A.

Xinjiawei 20W PD fast charging adopts CX7509+CX7538

During the disassembly of Xinjiawei 20W PD

The entire DEMO board is quite compact and compact

Through observation, it was found that the main control chip of the Xinjiawei 20W PD charger switch power supply adopts CX7509, which is a current mode PWM control chip with a built-in 650V high-voltage power MOSFET. It is applied to solutions with power below 18W. Working in PWM mode at a fixed switching frequency, which is precisely set internally.

When under no load or light load, the working frequency is adjusted internally by the IC, and the chip can operate in green mode to reduce losses during light load and improve the overall work efficiency. During startup and operation, only a small current is required. A large resistor can be used in the startup circuit to further reduce power consumption during standby. The chip is equipped with a slope compensation circuit, which avoids the occurrence of subharmonic oscillations and improves system stability when the circuit operates at a high duty cycle.

Xinjiawei 20W PD fast charging adopts CX7509+CX7538

The CX7538 is a high-performance synchronous rectification control circuit for the secondary side of a switching power supply. In low voltage and high current switching power supply applications, it easily meets 6-level energy efficiency and is an ideal solution for ultra-low conduction voltage drop rectification devices.

The CX7538 can support switching frequency applications up to 150kHz, as well as switching power supply operating modes such as CCM/QR/DCM. Its extremely low conduction voltage drop generates much less loss than the conduction loss of Schottky diodes, greatly improving the conversion efficiency of the system and significantly reducing the temperature of rectifier devices.

The CX7538 has a built-in NMOSFET synchronous rectifier switch with a withstand voltage of up to 85V, and has extremely low internal resistance. The typical RdsON is as low as 10m Ω, which can provide system output up to 3A applications; It also has built-in high-voltage direct detection technology, with a withstand voltage of up to 200V; And with a power supply voltage of up to 30V, the controller can directly use an output voltage of up to 24V for rectification applications, greatly expanding the range of use.

There is a protocol chip on the other side of the small board.

The protocol chip adopts CX2919C, which has passed USB PD3.0 certification and supports fast charging protocols such as QC2.0, QC3.0, AFC, FCP, SCP, HVSCP, PD, and PPS. It can be configured with 5V, 9V, 12V voltage ranges and a maximum output power of 36W.

The CX2919C internally integrates a 10m Ω VBUS channel power switch transistor and a 10m Ω current detection resistor, supporting comprehensive protection functions, saving the number of peripheral components, simplifying circuits, and reducing costs. Encapsulated using ESOP8.

The Xinjiawei 20W PD charger is compatible with multiple fast charging protocols such as QC2.0/3.0, AFC, FCP, PD3.0, and PPS. It also has two PPS voltage ranges of 3.3-5.9V3A and 3.3-11V1.8A, which not only meets the fast charging requirements of iPhone 12 20W, but also has good compatibility with other brand phones.