SD6834

SD6834 is a current-mode PWM+PFM controller series with built-in high-voltage MOSFET and external sampling resistor for switched-mode power supplies. The circuit features low standby power consumption and low startup current. In standby mode, the circuit enters hiccup mode to effectively reduce standby power consumption. The switching center frequency ranges from 25 to 67KHz depending on load. The dithered switching frequency enables lower EMI. A built-in peak current compensation circuit ensures consistent peak current limiting across different AC input voltages. At power-up, the peak current compensation is at maximum and gradually reaches equilibrium, reducing transformer stress during power-up and preventing transformer saturation. The peak current limit can also be adjusted via the CS pin resistor. The circuit integrates various fault protection functions, including UVLO, OVP, OLP, leading-edge blanking, primary overcurrent protection, and thermal protection. After a protection event is triggered, the circuit automatically restarts repeatedly until the system returns to normal operation.

Key features

• Energy Star 2.0 compliant
• Low startup current (3μA)
• Load-dependent switching frequency for improved efficiency
• Dithered switching frequency for reduced EMI
• OVP, primary-side OCP, overload, and OTP protection
• External peak current sense resistor
• UVLO
• Integrated high-voltage MOSFET
• Auto-restart
• Peak current compensation circuit
• Initial peak current maximum compensation
• Hiccup mode
• Cycle-by-cycle current limiting