ACT511
Product Brief, 05-Dec-12
ActiveQRTM Quasi-Resonant PWM Controller
FEATURES
• Quasi-Resonant Operation
• Adjustable up to 75kHz Switching Frequency
• Accurate OCP/OLP Protection
• Integrated Patented Frequency Foldback
Technique
• Integrated Patented Line and Primary
Inductance Compensation
• Built-in Soft-Start Circuit
• Line Under-Voltage, Thermal, Output Over-
voltage, Output Short Protections
• Current Sense Resistor Short Protection
• Transformer Short Winding Protection
• 100mW Standby Power
• Complies with Global Energy Efficiency and
CEC Average Efficiency Standards
• Tiny SOT23-6 Packages
good margin.
ACT511 integrates comprehensive protection. In
case of over temperature, over voltage, short
winding, short current sense resistor, open loop an
d overload conditions, it would enter into auto
restart mode including Cycle-by-Cycle current
limiting.
ACT511 is to achieve no overshoot and very short
rise time even with big capacitive load (4000µF)
with the built-in fast and soft start process.
The Quasi-Resonant (QR) operation mode can
effectively improve efficiency, reduce the EMI noise
and further reduce the components in input filter.
ACT511 is for application up to 60 Watt.
Figure 1:
Simplified Application Circuit
APPLICATIONS
• AC/DC Adaptors/Chargers for Cell Phones,
Cordless Phone, PDAs, E-books
• Adaptors for Portable Media Player, DSCs,
Set-top boxes, DVD players, records
• Linear Adapter Replacements
GENERAL DESCRIPTION
The ACT511 is a high performance peak current
mode PWM controller. ACT511 applies ActiveQRTM
and frequency foldback technique to reduce EMI
and improve efficiency. ACT511’s maximum
switching frequency is set at 90kHz. Very low
standby power, good dynamic response and
accurate voltage regulation is achieved with an
opto-coupler and the secondary side control circuit.
The burst mode operation enables low standby
power of 100mW with small output voltage ripple.
By applying frequency foldback and ActiveQRTM
technology, ACT511 increases the average system
efficiency compared to conventional solutions and
exceeds the latest ES2.0 efficiency standard with
Innovative PowerTM
-1-
ActiveQRTM is a trademark of Active-Semi.
www.active-semi.com
Copyright © 2012 Active-Semi, Inc.