It is a high-precision offline switching power supply circuit, applied to low-power AC/DC chargers and adapters.

The SP5710 is a high-precision offline switch-mode power supply circuit used in low-power AC/DC chargers and adapters. The SP5710 uses primary-side sensing for precise constant current and constant voltage control, eliminating the need for optocouplers and TL431 typically used in such applications.

In constant current mode, the output power is set by the sampling resistor Rs connected to the CS pin. In constant voltage mode, the chip's various operating modes ensure high overall conversion efficiency. Additionally, the chip incorporates line voltage drop compensation, resulting in good load regulation. The SP5710 operates in PFM mode under constant current and PWM mode under constant voltage, reducing frequency at light loads.

The SP5710 provides power-on soft-start and various self-recoverable protection features, including cycle-by-cycle current limiting (OCP), VDD overvoltage protection (OVP), VDD overvoltage clamping, and undervoltage lockout (UVLO). The SP5710's spread-spectrum frequency modulation provides improved EMI performance.

Typical Application Diagram

Features

  ● 5% constant voltage accuracy and 5% constant current accuracy across the full voltage range

● Uses primary-side feedback control, eliminating the need for optocouplers and TL431

● Externally adjustable constant current value and output power

● Built-in primary-side feedback constant current control

● Built-in adaptive peak current control

● Built-in primary inductance compensation

● Externally adjustable line voltage drop compensation

● Power-on soft start

● Built-in leading edge blanking (LEB) function

● Cycle-by-cycle current limiting protection (OCP)

● Undervoltage lockout (UVLO), overvoltage protection (OVP), VDD voltage clamping protection

● Overtemperature protection

● SOT23-6 package

Applications

● Mobile phone chargers

● PDA and digital camera chargers

● Auxiliary power supplies for televisions and personal computers

● Replacement for linear regulators and RCC power supplies