U3213E

U3213E is a high-performance, low-cost PWM-controlled power switch designed for offline low-power buck applications. The device requires minimal external components and a simple peripheral circuit. Its integrated high-voltage startup module and high-voltage-rated MOSFET help improve the system's surge withstand capability. Unlike conventional PWM power switches, U3213E has no fixed internal clock to drive the MOSFET; instead, the switching frequency adjusts automatically with load variations. The IC employs multi-mode PWM control technology, which effectively simplifies peripheral circuit design, improves line and load regulation, and eliminates audible noise during system operation. In addition, the internal peak current detection threshold is automatically adjusted based on actual load conditions, significantly reducing standby power consumption at no load. U3213E 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. This product family supports offline non-isolated buck and buck-boost topologies, and is suitable for small appliance power supplies and linear power supply replacement applications, featuring high output accuracy and low peripheral cost. The typical quiescent current is 200µA, reducing the required VDD capacitance and helping to improve system efficiency. The IC integrates a 200V high-voltage startup unit and an ultra-low standby power design (below 50mW). It employs cycle-by-cycle peak current limiting and leading-edge blanking (approximately 350ns). Through multi-mode operation combining amplitude modulation and frequency modulation control, efficiency is optimized and standby losses are reduced across different load conditions. A soft-start circuit with a typical duration of 4ms is integrated on-chip. Protection features include output overvoltage protection, overload/short-circuit protection, abnormal overcurrent protection, and overtemperature protection (triggered when junction temperature exceeds 150°C). Furthermore, U3213E integrates a fast dynamic response function to minimize output voltage drop during load transitions.

Applications

• Telecom 90V power systems
• Ethernet PoE
• Industrial control
• Inverter systems

Key features

• Integrated 5A 200V MOSFET
• Integrated 200V high-voltage startup circuit
• Multi-mode control, noiseless operation
• Supports buck and buck-boost topologies
• Default 14.3V output (FB pin floating)
• Standby power consumption below 50mW
• Excellent line and load regulation
• Integrated soft-start circuit
• Internal protection features: overload protection, cycle-by-cycle current limiting, output OVP, VDD overvoltage, undervoltage, and voltage clamp protection