Description

SC2569 combines a highly integrated current

mode PWM control IC optimized for high

performance, low standby power and cost

effective off line flyback converter applications.

PWM switching frequency at normal operation is

externally programmable and trimmed to tight

range. At no load or light load condition, the IC

operates is extended ‘burst mode’ to minimize

switching loss. Lower standby power and higher

conversion efficiency is thus achieved.

VDD low startup current and low operating

current contribute to a reliable power on startup

and low standby design with SC2569. A large

value resistor could thus be used in the startup

circuit to minimize the standby power.

The internal slope compensation improves

system large signal stability and reduces the

possible sub-harmonic oscillation at high PWM

duty cycle output. Leading-edge blanking on

current sense input removes the signal glitch due

to snubber circuit diode reverse recovery. This

greatly helps to reduce the external component

count and system cost in application.

SC2569 offers complete protection coverage with

automatic self recovery feature including

Cycle-by-Cycle current limiting(OCP), over load

protection(OLP), VDD under voltage lockout

(UVLO), over temperature protection (OTP), and

over voltage protection (OVP). The Gate-drive

output is clamped at 18V to protect the power

MOSFET.

In SC2569, OCP threshold slope is internally

optimized to reach constant output power limit

over universal AC input range.

Excellent EMI performance is achieved with

internal frequency jitter technique and soft

switching control at the totem pole gate drive

output.

The tone energy at below 22KHz is minimized in

the design and audio noise is eliminated.

SC2569 is offered in both SOP-8 and DIP-8

packages.

Features

◆ Extended Burst Mode Control For Improved

Efficiency and Minimum Standby Power

Design

◆ Power-on Soft Start Reducing MOS Stress

◆ Audio Noise Free Operation

◆ External Programmable PWM Switching

Frequency

◆ Low VDD startup and operating current

◆ Frequency jitter to Minimize EMI

◆ Leading edge blanking on current sense

◆ Internal Synchronized Slope Compensation

◆ Low VIN/VDD Startup Current(6.5uA) and

Low Operating Current(2.0mA)

◆ Complete Protection Coverage With Auto

Self-Recovery

⚫ VDD Under Voltage Lockout with

Hysteresis (UVLO)

⚫ Cycle-by-Cycle over current Protection

⚫ Over load Protection (OLP)

⚫ Over Temperature Protection (OTP)

⚫ VDD Over Voltage Protection (OVP)

Applications

Offline AC/DC flyback converter for

◆ AC/DC Adapter

◆ Set-Top Box Power Supplies

◆ Auxiliary Power Supply

◆ Open-frame SMPS

◆ Battery Charger