FAN6747 データシートの表示（PDF） - Fairchild Semiconductor

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FAN6747

Highly Integrated Green-Mode PWM Controller

Fairchild Semiconductor 

September 2010

FAN6747

Highly Integrated Green-Mode PWM Controller

Features

ƒ High-Voltage Startup

ƒ AC-Line Brownout Protection by HV Pin

ƒ Constant Output Power Limit by HV Pin

(Full AC-Line Range)

ƒ Built-in 8ms Soft-Start Function

ƒ Two-Level Over-Current Protection (OCP) with

220ms Debounce

ƒ Short-Circuit Protection (SCP) with 15ms Debounce

as Output Short

ƒ Peak-Current Mode Operation with Cycle-by-Cycle

Current Limiting

ƒ Low Startup Current: 30µA

ƒ Low Operating Current: 1.7mA

ƒ Over-Temperature Protection (OTP) with an

External Negative-Temperature-Coefficient (NTC)

Thermistor

ƒ PWM Frequency Decreasing at Green-Mode

ƒ VDD Over-Voltage Protection (OVP)

ƒ Internal Latch Circuit for OVP, OTP, SCP, and OCP

Applications

General-purpose switch-mode power supplies and

flyback power converters, including:

ƒ Power Adapters

ƒ SMPS with Peak-Current Output, such as for

Printers, Scanners, Motor Drivers

ƒ AC/DC NB Adapters

ƒ Open-Frame SMPS

Description

The highly integrated FAN6747 PWM controller

provides several features to enhance the performance

of flyback converters. To minimize standby power

consumption, a proprietary green-mode function

provides off-time modulation to decrease the switching

frequency with load condition.

Under zero-load condition, the power supply enters

burst mode and burst frequency can be low to save

more power. Green-mode function enables the power

supply to meet international power conservation

requirements.

The FAN6747 is especially designed for SMPS with

peak-current output. It incorporates a cycle-by-cycle

current limiting and two-level Over-Current-Protection

(OCP) that can handle peak load with a debounce time.

Once the current is over the threshold level, it triggers

the first counter 15ms and checks if VDD is below 10V; if

it is, the PWM latches off for SCP. If VDD is higher than

10V; it keeps counting to 220ms, then the PWM latches

off for OCP.

FAN6747 also integrates a frequency-hopping function

internally to help reduce EMI emission of a power

supply with minimum line filters. Built-in proprietary

internal synchronized slope compensation achieves

constant output power limit over universal AC line

range. The gate output is clamped at 14V to protect the

external MOSFET from over-voltage damage.

Other protection functions include AC-line brownout

protection with hysteresis and VDD over-voltage

protection. For over-temperature protection, an external

NTC thermistor can be applied to sense the ambient

temperature. When OCP, OVP, SCP, or OTP is

activated, an internal latch circuit latches off the

controller. The latch is reset when the VDD supply is

removed.

Ordering Information

Part Number

FAN6747LMY

Operating

Temperature Range

-40 to +105°C

Package

8-Lead, Small-Outline Integrated Circuit (SOIC),

JEDEC MS-012, .15-Inch Narrow Body

Packing

Method

Tape & Reel

© 2010 Fairchild Semiconductor Corporation

FAN6747 • Rev. 1.0.3

www.fairchildsemi.com

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