Application Solution for GX8809 Mobile Phone Charger with AC/DC PSR Switching Power Supply Chip, Replacing MD8809

The performance of the switch power chip in a mobile phone charger directly affects the user experience. The switch power chip determines the overall quality of the mobile phone charger, such as efficiency, safety, and portability. This article mainly introduces an AC/DC PSR switching power supply chip GX8809 used for mobile phone chargers. The charger scheme has a simple external circuit, multiple charging options, and good status information response, meeting various requirements for charger charging.

The GX8809 switching power supply chip adopts advanced primary edge control technology, without the need for optocouplers or other feedback components on the periphery. It is specifically designed for high-performance, peripheral circuit simplified AC to DC switching power supplies. The chip can also directly replace MD8809 and has the same excellent performance.

The GX8809 integrates PFM modulation controller and power BJT internally, using CV and CC regulation to achieve high output accuracy, stability, and reliability of the chip. In terms of safety, the chip provides extremely comprehensive and high-performance intelligent protection functions, including cycle by cycle overcurrent detection (external CS resistance can be set), overload protection, overvoltage protection, short circuit protection, and its soft start function. When the chip is under light load, it uses frequency down regulation and burping operation, resulting in a lower standby power consumption of 30mW for GX8809.

Power off chip GX8809 features introduction:

Wide input communication range: 90Vac~265Vac

• Output power: 3~5W

• Operating frequency up to 70KHz

Excellent system ESD performance

Adjustable output linear compensation (3%~8%)

• Adjustable input linear compensation

• High efficiency quasi resonant working mode

Built in short-circuit protection, output overvoltage protection, and over temperature protection

In addition, the frequency jitter and soft start function of GX8809 chip make it have good EMI characteristics, providing a very good control method for low-power power supply systems developed by customers using flyback architecture. It is applied to chargers, thermostats, smart switches, and secondary market smart meters, providing a good implementation method.