A high-performance synchronous rectifier control circuit on the secondary side of a switching power supply

The SP6539F is a high-performance synchronous rectifier control circuit for secondary-side switching power supplies. In low-voltage, high-current switching power supply applications, it easily meets Tier 6 energy efficiency standards and is an ideal solution for ultra-low conduction voltage drop rectifier devices. The chip supports switching frequencies up to 150kHz and supports switching power supply operating modes such as CCM/QR/DCM. The extremely low conduction voltage drop results in significantly lower power loss compared to Schottky diodes, greatly improving system conversion efficiency and significantly reducing rectifier device temperature.

The chip integrates a 100V NMOSFET synchronous rectifier switch with very low internal resistance, with a typical RdsON as low as 11mΩ, providing a system output of up to 3A. It also integrates high-voltage direct detection technology with a voltage rating up to 200V and a supply voltage up to 30V, allowing the controller to be directly used in rectification applications with output voltages as high as 24V, greatly expanding its range of applications.

The highly integrated circuit design makes the chip's external circuitry extremely simple. In QC and PD 5V/9V/12V applications, only one capacitor is needed to build a complete synchronous rectification system.

Typical Application Diagram

Functions

● Supports switching power supply CCM/QR/DCM modes

● Excellent 5V/9V/12V fast charging synchronous rectification application

● Built-in MOS with a voltage rating up to 100V

● Built-in MOS on-resistance as low as 11mΩ

● Efficiency improvement of 2~6% compared to traditional Schottky diodes

● Extremely wide operating voltage range of 4.5V to 36V

● Can be powered directly by 5V or by an auxiliary winding

● Static operating current as low as 600μA

● Supports switching power supply frequencies up to 150kHz

● SOP8 package

Applications

  ● 5V3A~12V3A, fast charging power supply

● 18W-PD fast charging power supply

● High-efficiency switching power supply