Fairchild FAN6747 Data Handbook
Summary
Maximize power efficiency in your electronic designs with this highly integrated Green-Mode PWM Controller. Essential for developing stable Switch-Mode Power Supplies (SMPS) and flyback converters, it features patented green-mode technology, AC line brownout protection, soft-start functionality, and robust multi-level safeguards (OCP, OVP, SCP, OTP). Ideal for engineers building general power adapters, printers, motor drivers, and AC/DC supplies that require high reliability and meet modern international energy conservation standards.
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FA 6747 — ighly Integrated G reen-M ode PW ontroller
September 2010
FAN6747 Highly Integrated Green-Mode PWM Controller
Features
Description
High-Voltage Startup The highly integrated FAN6747 PWM controller
provides several features to enhance the performance
AC-Line Brownout Protection by HV Pin
of flyback converters. To minimize standby power
Constant Output Power Limit by HV Pin consumption, a proprietary green-mode function (Full AC-Line Range) provides off-time modulation to decrease the switching
frequency with load condition.
Built-in 8ms Soft-Start Function
Under zero-load condition, the power supply enters
Two-Level Over-Current Protection (OCP) with
burst mode and burst frequency can be low to save
220ms Debounce
more power. Green-mode function enables the power
Short-Circuit Protection (SCP) with 15ms Debounce supply to meet international power conservation as Output Short requirements. Peak-Current Mode Operation with Cycle-by-Cycle The FAN6747 is especially designed for SMPS with Current Limiting peak-current output. It incorporates a cycle-by-cycle
current limiting and two-level Over-Current-Protection
Low Startup Current: 30µA
(OCP) that can handle peak load with a debounce time.
Low Operating Current: 1.7m A Once the current is over the threshold level, it triggers
the first counter 15ms and checks if VDD is below 10V; if
Over-Temperature Protection (OTP) with an
it is, the PWM latches off for SCP. If VDD is higher than
External Negative-Temperature-Coefficient (NTC)
10V; it keeps counting to 220ms, then the PWM latches
Thermistor
off for OCP.
PWM Frequency Decreasing at Green-Mode
FAN6747 also integrates a frequency-hopping function
VDD Over-Voltage Protection (OVP) internally to help reduce EMI emission of a power
supply with minimum line filters. Built-in proprietary
Internal Latch Circuit for OVP, OTP, SCP, and OCP
internal synchronized slope compensation achieves constant output power limit over universal AC line
Applications range. The gate output is clamped at 14V to protect the
external MOSFET from over-voltage damage.
General-purpose switch-mode power supplies and flyback power converters, including: Other protection functions include AC-line brownout
protection with hysteresis and VDD over-voltage
Power Adapters
protection. For over-temperature protection, an external SMPS with Peak-Current Output, such as for NTC thermistor can be applied to sense the ambient Printers, Scanners, Motor Drivers temperature. When OCP, OVP, SCP, or OTP is activated, an internal latch circuit latches off the
AC/DC NB Adapters
controller. The latch is reset when the VDD supply is Open-Frame SMPS removed.
Ordering Information
Part Number Operating
Temperature Range Package Packing Method
FAN6747LMY -40 to +105°C 8-Lead, Small-Outline Integrated Circuit (SOIC),
JEDEC MS-012, .15-Inch Narrow Body Tape & Reel
© 2010 Fairchild Semiconductor Corporation www.fairchildsemi.com FAN6747 • Rev. 1.0.3
Page Summary Contents For Fairchild FAN6747 Data Handbook
Manual Details
| Brand | Fairchild |
|---|---|
| Pages | 15 |
| File Size | 778.97 KB |
| Published | July 22, 2026 |
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Frequently Asked Questions
What component placement guidelines should I follow for optimal performance?
Locate compensation and filter components near the FAN6747, and avoid using excessively long PCB traces.
How does the device achieve low standby power consumption?
It uses a proprietary green-mode function that adjusts off-time modulation to decrease switching frequency based on load condition.
Is there a specific capacitor recommended for stable circuit operation?
Yes, placing a 0.1µF decoupling capacitor between VDD and GND is strongly recommended.
What does the Over-Current Protection (OCP) feature manage?
The twofold level OCP monitors current and can enter burst mode to ensure power draw remains within specified limits.