ACT512
Product Brief, 18-Feb-14
TM
ActiveQR Quasi-Resonant PWM Controller
ACT512 integrates comprehensive protection. In
FEATURES
case of over temperature, over voltage, winding
CCM and Quasi-Resonant Operation
short, current sense resistor short, open loop and
overload conditions, it would enter into auto restart
Adjustable up to 75kHz Switching Frequency
mode including Cycle-by-Cycle current limiting.
OCP/OLP Protection
ACT512 is to achieve no overshoot and very short
Integrated Patented Frequency Foldback
rise time even with a big capacitive load with the
Technique
built-in fast and soft start process.
Integrated Patented Line Compensation
In full load condition, ACT512 is able to be
designed to work in both CCM mode and DCM
Built-in Soft-Start Circuit
mode to meet different types of applications. Quasi-
Line Under-Voltage, Thermal, Output Over-
Resonant (QR) operation mode can improve
voltage, Output Short Protections
efficiency during DCM operation, and reduce EMI
Current Sense Resistor Short Protection and further reduce the components in input filter.
Transformer Winding Short Protection
ACT512 is ideal for applications up to 60 Watts.
100mW Standby Power
Figure 1:
Complies with Global Energy Efficiency and
Simplified Application Circuit
CEC Average Efficiency Standards
Tiny SOT23-6 Packages
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
TM
mode PWM controller. ACT512 applies ActiveQR
and frequency foldback technique to reduce EMI
and improve efficiency. ACT512s 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.
TM
By applying frequency foldback and ActiveQR
technology, ACT512 increases the average system
efficiency compared to conventional solutions and
exceeds the latest ES2.0 efficiency standard with
good margin.
TM
Innovative Power - 1 - www.active-semi.com
TM
ActiveQR is a trademark of Active-Semi.
Copyright 2014 Active-Semi, Inc.
ACT512
Product Brief, 18-Feb-14
ORDERING INFORMATION
PACKING
PART NUMBER TEMPERATURE RANGE PACKAGE PINS TOP MARK
METHOD
ACT512US-T -40C to 85C SOT23-6 6 TUBE & REEL FSHT
PIN CONFIGURATION
SOT23-6
ACT512US
PIN DESCRIPTIONS
PIN NAME DESCRIPTION
Current Sense Pin. Connect an external resistor (R ) between this pin and ground to set peak
CS
1 CS
current limit for the primary switch.
2 GND Ground.
3 GATE Gate Drive. Gate driver for the external MOSFET transistor.
4 VDD Power Supply. This pin provides bias power for the IC during startup and steady state operation.
Valley Detector Pin. Connect this pin to a resistor divider network from the auxiliary winding to
5 VDET
detect zero-crossing points for valley turn on operation.
6 FB Feedback Pin. Connect this pin to optocouplerss collector for output regulation.
TM
Innovative Power - 2 - www.active-semi.com
TM
ActiveQR is a trademark of Active-Semi.
Copyright 2014 Active-Semi, Inc.