EVK-ACT512US-T Datasheet, PDF (1/4 Pages) Active-Semi, Inc – ActiveQRTM Quasi-Resonant PWM Controller

ACT512
Product Brief, 18-Feb-14
ActiveQR^TM Quasi-Resonant PWM Controller
FEATURES
• CCM and Quasi-Resonant Operation
• Adjustable up to 75kHz Switching Frequency
• OCP/OLP Protection
• Integrated Patented Frequency Foldback
Technique
• Integrated Patented Line Compensation
• Built-in Soft-Start Circuit
• Line Under-Voltage, Thermal, Output Over-
voltage, Output Short Protections
• Current Sense Resistor Short Protection
• Transformer Winding Short Protection
• 100mW Standby Power
• Complies with Global Energy Efficiency and
CEC Average Efficiency Standards
• Tiny SOT23-6 Packages
ACT512 integrates comprehensive protection. In
case of over temperature, over voltage, winding
short, current sense resistor short, open loop and
overload conditions, it would enter into auto restart
mode including Cycle-by-Cycle current limiting.
ACT512 is to achieve no overshoot and very short
rise time even with a big capacitive load with the
built-in fast and soft start process.
In full load condition, ACT512 is able to be
designed to work in both CCM mode and DCM
mode to meet different types of applications. Quasi-
Resonant (QR) operation mode can improve
efficiency during DCM operation, and reduce EMI
and further reduce the components in input filter.
ACT512 is ideal for applications up to 60 Watts.
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 ACT512 is a high performance peak current
mode PWM controller. ACT512 applies ActiveQR^TM
and frequency foldback technique to reduce EMI
and improve efficiency. ACT512’s maximum design
switching frequency is set at 75kHz. Very low
standby power, good dynamic response and
accurate voltage regulation is achieved with an
opto-coupler and the secondary side control circuit.
The idle mode operation enables low standby
power of 100mW with small output voltage ripple.
By applying frequency foldback and ActiveQR^TM
technology, ACT512 increases the average system
efficiency compared to conventional solutions and
exceeds the latest ES2.0 efficiency standard with
good margin.
Innovative Power^TM
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ActiveQR^TM is a trademark of Active-Semi.
www.active-semi.com
Copyright © 2014 Active-Semi, Inc.