UC3873A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 UC3873A is a high performance current mode PWMcontroller ideally suited for low standby power. Low VDD 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 UC3873A contains protection with automatic recoveryincluding OLP (over load protection), OCP (cycle-by-cycle currentlimiting), and UVLO (VDD over voltage clamp and under voltagelockout). It also provides the protections including OTP (overtemperature protection), OVP (over voltage protection) in UTCUC3873A with automatic recovery. To protect the power MOSFET,Gate-drive output is fixed up to 16V max.The internal slope compensation improves system stability at high PWM duty cycle output. Leading-edgeblanking on current sense input removes the signal glitch, which offering minimal external component count in thedesign. Excellent EMI performance is achieved with UTC proprietary frequency hopping technique(ZL201020615247.1) together with soft driver control. Audio noise is eliminated due to switch frequency more than20kHz during operation.The UTC UC3873A has such applications as: battery charger, power adaptor, set-top box power supplies, ink jetprinters, open-frame SMPS.

特性 Features

UTC proprietary frequency hopping technology for Improved EMI performance. Power-saving mode for high light-load and standby efficiency Soft Start Dynamic peak current limiting for constant output power Built-in synchronized slope compensation OLP with automatic recovery OTP and OVP( automatic recovery) VDD clamp for higher security Programming OTP for higher security Fixed switch frequency 65kHz Gate output voltage clamped at 16V Low start-up current Cycle-by-cycle current limiting Under voltage lockout (UVLO) Few external components required