Fairchild FAN6747, FAN6747 Schematic [ru]

FAN6747
Highly Integrated Green-Mode PWM Controller

FAN6747 — Highly Integrated Green-Mode PWM Controller

September 2010

Features

 High-Voltage Startup
 AC-Line Brownout Protection by HV Pin
 Constant Output Power Limit by HV Pin

(Full AC-Line Range)

 Built-in 8ms Soft-Start Function
 Two-Level Over-Current Protection (OCP) with

220ms Debounce

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

as Output Short

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

Current Limiting

 Low Startup Current: 30µA
 Low Operating Current: 1.7mA
 Over-Temperature Protection (OTP) with an

External Negative-Temperature-Coefficient (NTC)
Thermistor

 PWM Frequency Decreasing at Green-Mode
 V

Over-Voltage Protection (OVP)

DD

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

Applications

General-purpose switch-mode power supplies and
flyback power converters, including:

 Power Adapters
 SMPS with Peak-Current Output, such as for

Printers, Scanners, Motor Drivers

 AC/DC NB Adapters
 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 V
it is, the PWM latches off for SCP. If V
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 V
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 V
removed.

is below 10V; if

DD

is higher than

DD

over-voltage

DD

supply is

DD

Ordering Information

Part Number

FAN6747LMY -40 to +105°C

© 2010 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6747 • Rev. 1.0.3

Operating

Temperature Range

Package

8-Lead, Small-Outline Integrated Circuit (SOIC),
JEDEC MS-012, .15-Inch Narrow Body

Packing

Method

Tape & Reel

Application Diagram

FAN6747 — Highly Integrated Green-Mode PWM Controller

Figure 1. Typical Application

Internal Block Diagram

4 3

Line Voltage
Sample Circuit

HV

Startup

7

VDD

RT

I

RT

5

V

V

1.05V

0.7V

UVLO

17V/10V

DD-OVP

DD-SCP

Brownout Protection

Debounce

Debounce1

Debounce2

V

limit

OVP

SCP

Adjustment

Internal

BIAS

OTP

OCP

SCP
OVP
OCP

Soft-Start

Circuit

Delay

Delay

SCP

OCP

Auto

Restart

Protection

SQ

R

OSC

PWM

Comparator

Current Limit

Comparator

OCP

Comparator

OLP

Comparator

Latch

Protection

Slope

Compensation

OTP

Green

Mode

4.6V

Soft

Driver

NCHV

8

GATE

5V

3R

1R

Blanking

Circuit

2

6

FB

SENSE

GND

Figure 2. Functional Block Diagram

© 2010 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6747 • Rev. 1.0.3 2

Marking Information

ZXYTT
6747F

TPM

Pin Configuration

: Fairchild Logo

Z: Plant Code

X: Year Code

Y: Week Code

TT: Die Run Code

F: L = OCP latch

T: Package Type (N =DIP, M = SOP)

P: Y =

Green Compound

M: Manufacturing Flow Code

Figure 3. Top Mark

FAN6747 — Highly Integrated Green-Mode PWM Controller

Pin Definitions

Pin # Name Description

1 GND

2 FB

3 NC

4 HV

5 RT

6 SENSE

7 VDD

8 GATE

Ground. This pin is used for the ground potential of all the pins. A 0.1µF decoupling capacitor
placed between VDD and GND is recommended.

Feedback. The output voltage feedback information from the external compensation circuit is fed
into this pin. The PWM duty cycle is determined from this pin and the current-sense signal from
Pin 6.

No Connection.

High-Voltage Startup. This pin is connected to the line input via diodes and resistors to achieve

brownout and high/low line compensation. Once the voltage of the HV pin is lower than the
brownout voltage, PWM output is turned off. High/low line compensation dominates the OCP
level and cycle-by-cycle current limit, to solves the unequal OCP level and power limit problem
under universal input.

Over-Temperature Protection. For over-temperature protection, an external NTC thermistor is
connected from this pin to GND. The impedance of the NTC decreases at high temperatures.
Once the voltage of the RT pin drops below the threshold voltage, the controller latches off the

If the RT pin is not connected to the NTC resistor for over temperature protection, it is

PWM.
recommended to connect one 100KΩ resistor to ground to prevent noise interference. This pin is
limited by internal clamping circuit.

Current Sense. This pin is used to sense the MOSFET current for the current mode PWM and
OCP. If the switching current is higher than OCP threshold and lasts 220ms, the controller
latches off the PWM.

Supply Voltage. IC operating current and MOSFET driving current are supplied using this pin.
This pin is connected to an external bulk capacitor of typically 10µF. The threshold voltages for
startup and turn-off are 16.5V and 9V, respectively. The operating current is lower than 2mA.

Gate Driver Output. The totem-pole output driver for the power MOSFET. It is internally
clamped below 14V.

Figure 4. Pin Assignments

© 2010 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6747 • Rev. 1.0.3 3

FAN6747 — Highly Integrated Green-Mode PWM Controller

Absolute Maximum Ratings

Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be
operable above the recommended operating conditions and stressing the parts to these levels is not recommended.
In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability.
The absolute maximum ratings are stress ratings only.

Symbol Parameter Min. Max. Unit

VDD DC Supply Voltage 30 V

VHV

VL Input Voltage to FB, SENSE, RT Pin -0.3 7.0 V

PD Power Dissipation (TA<50°C) 400 mW

ΘJA

TJ Operating Junction Temperature -40 +125 °C

T

TL Lead Temperature (Soldering, 10 Seconds) +260 °C

ESD

Notes:

1. Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device.

2. All voltage values, except differential voltages, are given with respect to the network ground terminal.

Suddenly Input Voltage to HV Pin within 1 Second (Series connect with

)

R

HV

Thermal Resistance (Junction-to-Ambient) 150 °C/W

Storage Temperature Range -55 +150 °C

STG

Electrostatic Discharge Capability,
All Pins Except HV Pin

Human Body Model, JESD22-A114 4.50

Charge Device Model, JESD22-C101 1.5

640 V

kV

Recommended Operating Conditions

The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended
operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not
recommend exceeding them or designing to Absolute Maximum Ratings.

Symbol Parameter Conditions Min. Typ. Max. Unit

TA Operating Ambient Temperature -40 +105 °C

VHV Input Voltage to HV Pin 500 V

RHV

HV Startup Resistor

150 200 250 kΩ

© 2010 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6747 • Rev. 1.0.3 4

Electrical Characteristics

VDD=15V and TA=25°C, unless otherwise specified.

Symbol Parameter Conditions Min. Typ. Max. Units

VDD Section

VOP Continuously Operating Voltage 24 V

V

Turn-On Threshold Voltage 15.5 16.5 17.5 V

DD-ON

V

PWM Turn-Off Threshold Voltage 8 9 10 V

DD-OFF

Threshold Voltage on VDD for HV

V

DD-OLP

JFET Turn-On in Protection
Condition

V

DD-LH

Threshold Voltage on VDD Pin
for Latch-Off Release Voltage

Threshold Voltage on VDD Pin

V

DD-AC

for Disable AC Recovery to Avoid
Startup Failed

V

DD-SCP

ILH

I

DD-ST

I

DD-OLP

I

DD-OP1

I

DD-OP2

Threshold Voltage on VDD Pin
for Short-Circuit Protection (SCP)

Holding Current Under Latch-Off
Conduction

Startup Current V

Holding Current at PWM-Off
Phase

Operating Supply Current when
PWM Operating

Operating Supply Current when
PWM Stop

Threshold Voltage on VDD Pin

V

for V

DD-OVP

Over-Voltage Protection

DD

(Latch-Off)

t

D-OVP

VDD OVP Debounce Time VFB > V

After Trigger OCP/
SCP/ OVP/ OTP

5.5 6.5 7.5 V

3.5 4.0 4.5 V

V

> V

V

FB

FBO

=5V 80 100 120 μA

V

DD

– 0.16V 30 μA

DD-ON

+0.1V 210 270 330 μA

V

DD-OLP

=20V, VFB=3V

V

DD

Gate Open

=20V, VFB=3V

V

DD

Gate Open

DD-OFF

+2.5

V

DD-OFF

+0.5

1.7 2.0 mA

1.2 1.5 mA

V

DD-OFF

+3.0

V

DD-OFF

+1.0

V

DD-OFF

+3.5

V

DD-OFF

+1.5

V

V

24 25 26 V

75 160 245 μs

FB-N

FAN6747 — Highly Integrated Green-Mode PWM Controller

Figure 5. UVLO Specification

Continued on following pages…

© 2010 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6747 • Rev. 1.0.3 5