SC2569
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
