U3210B

U3210B is a high-performance, low-cost PWM control power switch designed for offline low-power buck applications. It features a simple peripheral circuit with a minimal component count. The device integrates a high-voltage (500V) MOSFET startup module, which helps enhance the system's surge withstand capability. Unlike conventional PWM power switches, U3210B has no fixed internal clock to drive the MOSFET; instead, the switching frequency automatically adjusts according to load variations. The chip employs multi-mode PWM control technology, which effectively simplifies peripheral circuit design, improves line and load regulation, and eliminates audible noise that may occur during system operation. In addition, the internal peak current detection threshold automatically adjusts based on actual load conditions, thereby significantly reducing standby power consumption at no load. U3210B integrates comprehensive self-recovering protection features, including VDD undervoltage lockout, cycle-by-cycle current limiting, output overvoltage protection, overtemperature protection, overload protection, and VDD overvoltage protection.

Applications

• Small appliance power supplies
• Industrial control

Key features

• Integrated 9Ω, 500V MOSFET with 500V high-voltage startup circuit
• Integrated freewheeling diode
• Multi-mode control for noise-free operation
• Buck and buck-boost topology support, default 12V output (FB pin floating)
• Standby power consumption below 50 mW
• Excellent line and load regulation
• Integrated soft-start circuit
• Built-in comprehensive protection features: overload protection, cycle-by-cycle current limiting, output OVP, VDD OVP/UVP, and voltage clamp protection