www.fairchildsemi.com
FSCQ0765RT
TM
Green Mode Fairchild Power Switch (FPS ) for
Quasi-Resonant Switching Converter
Features
• Optimized for Quasi-Resonant Converter (QRC)
• Advanced Burst-Mode operation for under 1 W standby
power consumption
• Pulse by Pulse Current Limit (5A)
• Over load protection (OLP) - Auto restart
• Over voltage protection (OVP) - Auto restart
• Abnormal Over Current Protection (AOCP) - Latch
• Internal Thermal Shutdown (TSD) - Latch
• Under Voltage Lock Out (UVLO) with hysteresis
• Low Startup Current (typical : 25uA)
• Low Operating Current (typical : 4mA)
• Internal High Voltage SenseFET
OUTPUT POWER TABLE
(2)
230VAC ±15%
85-265VAC
PRODUCT
(1)
(1)
Open Frame
100 W
Open Frame
85 W
FSCQ0765RT
FSCQ1265RT
FSCQ1565RT
170 W
140 W
210 W
170 W
Table 1. Notes: 1. Maximum practical continuous power
in an open frame design at 50°C ambient. 2. 230 VAC or
100/115 VAC with doubler.
• Built-in Soft Start (20ms)
• Extended Quasi-resonant Switching for Wide Load Range
Typical Circuit
Application
• CTV
Vo
• DVD Receiver
• Audio Power Supply
AC
IN
Description
Drain
FSCQ0765RT
In general, Quasi-Resonant Converter (QRC) shows lower
EMI and higher power conversion efficiency compared to the
conventional hard switched converter with a fixed switching
frequency. Therefore, it is well suited for applications that are
sensitive to the noise, such as color TV and audio. The
FSCQ0765RT is an integrated Pulse Width Modulation
(PWM) controller and Sense FET specifically designed for
Quasi-resonant off-line Switch Mode Power Supplies
(SMPS) with minimal external components. The PWM
controller includes integrated fixed frequency oscillator, under
voltage lockout, leading edge blanking (LEB), optimized gate
driver, internal soft start, temperature compensated precise
current sources for a loop compensation and self protection
circuitry. Compared with discrete MOSFET and PWM
controller solution, it can reduce total cost, component count,
size and weight simultaneously increasing efficiency, produc-
tivity, and system reliability. This device is a basic platform
well suited for cost effective designs of Quasi resonant
switching flyback converters.
PWM
Sync
GND
VFB
Vcc
Figure 1. Typical Flyback Application
Rev.1.0.1
©2004 Fairchild Semiconductor Corporation