UNISONIC TECHNOLOGIES CO., LTD

UC3869

Preliminary

CMOS IC

www.unisonic.com.tw

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Copyright © 2016 Unisonic Technologies Co., Ltd

QW-R103-110.c

HIGH VOLTAGE GREEN MODE

PWM CONTROLLER

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DESCRIPTION

The UTC UC3869 is a highly integrated current mode PWM

control IC with high voltage start up, optimized for high

performance, low standby power consumption and cost effective

offline flyback converter applications.

PWM switching frequency at normal operation is internally fixed

and is trimmed to a tight range. At no load condition, the IC

operates in power-saving mode for lower standby power,

decreasing frequency for Higher conversion efficiency at light load

condition. The internal slope compensation improves system

stability at high PWM duty cycle output. Leading-edge blanking on

current sense input removes the signal glitch, which offering

minimal external component count in the design.

The UTC UC3869 offers complete protection coverage

lockout (UVLO), over load protection (OLP), over temperature

protection (OTP), and over voltage protection (OVP). 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 than 20kHz

during operation. The tone energy at below 22KHZ is minimized to

avoid audio noise during operation.

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FEATURES

* High voltage startup

* Power on soft start reducing MOSFET Vds stress

* Efficiency and minimum standby power

* Frequency shuffling for EMI

* Audio noise free operation

* Fixed 65KHZ switching frequency

* Comprehensive protection coverage

Cycle-by-cycle over current protection (OCP)

Overload Protection (OLP)

External programmable Over Temperature Protection (OTP)