UC3801中文资料LOW COST POWER-SAVING MODE PWM CONTROLLER FOR FLYBACK CONVERTERS数据手册UTC规格书

描述 Description

The UTC UC3801 provides a CCM/valley switching mixedmode operation for better efficiency performance. The operationmode stays at CCM at heavy load, and switch to valley switching atlight load.The UTC UC3801 is a high performance current mode PWMcontroller ideally suited for low standby power. Low VCC startupcurrent make the power reliable on startup design and a largevalue resistor could be used in the startup circuit to minimize thestandby power. At no load condition, the IC operates inpower-saving mode for lower standby power, decreasing frequencyfor Higher conversion efficiency at light load condition.The UTC UC3801 contains protection with automatic recoveryincluding OLP (over load protection), OCP (cycle-by-cycle currentlimiting), and UVLO (VCC over voltage clamp and under voltagelockout). It also provides the protections including OTP (overtemperature protection), BNO(AC Brown Out protection) , LNO(ACOver voltage protection), OVP (VCC or DC output over voltageprotection) with automatic recovery. To protect the powerMOSFET, Gate-drive output is fixed up to 16V max.The internal slope compensation improves system stability athigh PWM duty cycle output. Leading-edge blanking on currentsense input removes the signal glitch, which offering minimaexternal component count in the design. Excellent EMIperformance is achieved with UTC proprietary frequency hoppingtechnique (ZL201020615247.1) together with soft driver control.Audio noise is eliminated due to switch frequency more than 20kHzduring operation.UTC UC3801 is packaged by using tiny SOT-26 package. It hassuch applications as: battery charger, power adaptor, set-top boxpower supplies, ink jet printers, open-frame SMPS.

特性 Features

Proprietary frequency hopping for Improved EMI performance Cycle-by-cycle current limiting CCM/Valley Switching Operation Fixed switch frequency 60~70kHz Dynamic peak current limiting for constant output power Built-in synchronized slope compensation Gate output voltage clamped at 16V Adjustable DC output OVP/UVP/OTP OLP/VCC OVP/OTP/BNO/LNO (automatic recovery) Internal Soft Start