SDH8634

SDH8634 is a current-mode PWM+PFM controller for switching power supplies, integrating a high-voltage MOSFET, a high-voltage startup constant current source, and an external sampling resistor. SDH8634 features a built-in high-voltage startup constant current source with low standby power consumption < 30mW. Multiple control modes are supported: PWM mode under heavy load; PFM mode under light load to improve conversion efficiency; and hiccup mode under no-load condition to reduce standby power consumption. SDH8634 incorporates a frequency dithering function to reduce EMI. A built-in peak current compensation circuit ensures consistent maximum output power across different AC input voltages. The built-in soft-start function reduces transformer stress during power-up and prevents transformer saturation. SDH8634 integrates comprehensive protection features, including Leading Edge Blanking (LEB), cycle-by-cycle peak current limiting, VCC OVP, output OLP, and OTP. DIP-8-300-2.54

Applications

• Switching power supply

Key features

• High-voltage startup
• Low standby power < 30mW
• Multiple control modes
• Frequency jitter
• Peak current compensation
• Soft start
• Leading edge blanking (LEB)
• Cycle-by-cycle peak current limiting
• VCC OVP
• Output OLP
• OTP