Fairchild FAN7602B service manual

FAN7602B Green Current-Mode PWM Controller

FAN7602B — Green Current-Mode PWM Controller

March 2007

Features

 Green Current-Mode PWM Control  Fixed 65kHz Operation  Internal High-Voltage Start-up Switch  Burst-Mode Operation  Line Voltage Feedforward to Limit Maximum Power  Line Under-Voltage Protection  Latch Protection & Internal Soft-Start (10ms) Function  Overload Protection  Over-Voltage Protection  Low Operation Current: 1mA Typical  8-pin DIP/SOP

Applications

 Adapter  LCD Monitor Power  Auxiliary Power Supply

Related Application Notes

 AN6014 - Green Current Mode PWM Controller

FAN76 02

Description

The FAN7602B is a green current-mode PWM controller. It is specially designed for off-line adapter applications; DVDP, VCR, LCD monitor applications; and auxiliary power supplies.

The internal high-voltage start-up switch and the burstmode operation reduce the power loss in standby mode. As a result, it is possible to supply 0.5W load, limiting the input power under 1W when the input line voltage is

. On no-load condition, input power is under 0.3W.

265V

AC

The maximum power can be limited constantly, regardless of the line voltage change, using the power limit function.

The switching frequency is internally fixed at 65kHz.

The FAN7602B includes various protections for the system reliability and the internal soft-start prevents the output voltage over-shoot at start-up.

Ordering Information

Operating Temp.

Part Number

FAN7602BN

FAN7602BM

FAN7602BMX Tape & Reel FAN7602B

FAN7602B Rev. 1.0.0

Range Pb-Free Package Packing Method

8-DIP Rail FAN7602B

-25°C to +125°CYes 8-SOP

Rail FAN7602B

Marking

Code

Typical Application Diagram

Internal Block Diagram

FAN7602B — Green Current-Mode PWM Controller

FAN7602B

Figure 1. Typical Flyback Application

LUVP

Latch/

Plimit

1

2

2V/1.5V

10ms

Soft Start

65kHz clock

4V

Plimit

Offset

Generator

Latch

LUVP

OLP

OVP

Latch

SS End

Plimit

Offset

Auto Restart

Protection

Latch

Protection

Soft

Start

OLP

Circuit

PWM Block

VSTR

Reset

V

CC

8

6

V

CC

OVP

5V Ref

Delay

Circuit

PWM+

SS End

0.95V/0.88V

Soft

Start

UVLO

Driver Circuit

Power Limit

Plimit

Offset

12V/8V

Plimit

Offset

19V

5

3

4

OUT

CS/FB

GND

Figure 2. Functional Block Diagram of FAN7602B

FAN7602B Rev. 1.0.0 2

Pin Assignments

FAN7602B — Green Current-Mode PWM Controller

V

STR

NC V

CC

6 58 7

FAN7602B

YWW

1 2

Latch/

Plimit

Figure 3. Pin Configuration (Top View)

Pin Definitions

Pin # Name Description

1LUVP

2 Latch/Plimit

3CS/FB

4GND

5OUT

6V

CC

7NCNo Connection.

8V

STR

Line Under-Voltage Protection Pin. This pin is used to protect the set when the input voltage is lower than the rated input voltage range.

Latch Protection and Power Limit Pin. When the pin voltage exceeds 4V, the latch protection works; the latch protection is reset when the V For the power limit function, the OCP level decreases as the pin voltage increases.

Current Sense and Feedback Pin. This pin is used to sense the MOSFET current for the current mode PWM and OCP. The output voltage feedback information and the current sense information are added using an external RC filter.

Ground Pin. This pin is used for the ground potential of all the pins. For proper operation, the signal ground and the power ground should be separated.

Gate Drive Output Pin. This pin is an output pin to drive an external MOSFET. The peak sourcing current is 450mA and the peak sinking current is 600mA. For proper operation, the stray inductance in the gate driving path must be minimized.

Supply Voltage Pin. IC operating current and MOSFET driving current are supplied using this pin.

Start-up Pin. This pin is used to supply IC operating current during IC start-up. After

start-up, the internal JFET is turned off to reduce power loss.

3 4

GNDCS/FBLUVP

Out

voltage is lower than 5V.

CC

FAN7602B Rev. 1.0.0 3

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 Value Unit

V

CC

, I

I

OH

V

CS/FB

V

LUVP

V

Latch

V

STR

T

J

T

A

T

STG

P

D

V

ESD_HBM

V

ESD_MM

V

ESD_CDM

OL

Supply Voltage 20 V

Peak Drive Output Current +450/-600 mA

CS/FB Input Voltage -0.3 to 20 V

LUVP Input Voltage -0.3 to 10 V

Latch/Plimit Input Voltage -0.3 to 10 V

V

Input Voltage 600 V

STR

Operating Junction Temperature 150 °C

Operating Temperature Range -25 to 125 °C

Storage Temperature Range -55 to 150 °C

Power Dissipation 1.2 W

ESD Capability, Human Body Model 2.0 kV

ESD Capability, Machine Model 200 V

ESD Capability, Charged Device Model 500 V

FAN7602B — Green Current-Mode PWM Controller

Thermal Impedance

Symbol Parameter Value Unit

θ

JA

Note:

1. Regarding the test environment and PCB type, please refer to JESD51-2 and JESD51-10.

Thermal Resistance, Junction-to-Ambient 8-DIP 100 °C/W

FAN7602B Rev. 1.0.0 4

FAN7602B — Green Current-Mode PWM Controller

Electrical Characteristics

VCC = 14V, TA = -25°C~125°C, unless otherwise specified

Symbol Parameter Condition Min. Typ. Max. Unit

START UP SECTION

V

I

STR

Start-up Current V

STR

UNDER VOLTAGE LOCK OUT SECTION

Vth(start) Start Threshold Voltage VCC increasing 11 12 13 V

(stop) Stop Threshold Voltage VCC decreasing 7 8 9 V

V

th

HY(uvlo) UVLO Hysteresis 3.6 4.0 4.4 V

SUPPLY CURRENT SECTION

I

STR

CC

Start-up Supply Current TA = 25°C 250 320 μA

Operating Supply Current Output no switching 1.0 1.5 mA

SOFT-START SECTION

t

SS

Soft-Start Time

(1)

PWM SECTION

f

OSC

V

CS/FB1

D

t

D

MAX

MIN

Operating Frequency V

CS/FB Threshold Voltage TA = 25°C 0.9 1.0 1.1 V

Propagation Delay to Output

(1)

Maximum Duty Cycle 70 75 80 %

Minimum Duty Cycle 0 %

BURST MODE SECTION

V

CS/FB2

V

CS/FB3

Burst On Threshold Voltage TA = 25°C 0.84 0.95 1.06 V

Burst Off Threshold Voltage TA = 25°C 0.77 0.88 0.99 V

POWER LIMIT SECTION

K

Plimit

Offset Gain V

OUTPUT SECTION

V

OH

V

OL

t

R

t

F

Output Voltage High TA = 25°C, I

Output Voltage Low TA = 25°C, I

Rising Time

Falling Time

(1)

PROTECTION SECTION

V

Latch

t

OLP

t

OLP_ST

V

OLP

V

LUVPoff

V

LUVPon

V

OVP

Latch Voltage 3.6 4.0 4.4 V

Overload Protection Time

(1)

Overload Protection Time at Startup

Overload Protection Level 0 0.1 V

Line Under-Voltage Protection On to Off

Line Under-Voltage Protection Off to On

Over-Voltage Protection TA = 25°C 18 19 20 V

Note:

1. These parameters, although guaranteed by design, are not tested in production.

= 30V, TA = 25°C 0.7 1.0 1.4 mA

STR

51015ms

= 0.2V, TA = 25°C596573kHz

CS/FB

100 150 ns

Latch/Plimit

= 2V, TA = 25°C 0.12 0.16 0.20

= 100mA 11.5 12.0 14.0 V

source

= 100mA 1.0 2.5 V

sink

TA = 25°C, CL = 1nF 45 150 ns

TA = 25°C, CL= 1nF 35 150 ns

20 22 24 ms

30 37 44 ms

T

= 25°C 1.9 2.0 2.1 V

A

= 25°C 1.4 1.5 1.6 V

T

A

FAN7602B Rev. 1.0.0 5

Typical Performance Characteristics

FAN7602B — Green Current-Mode PWM Controller

12.8

12.4

[V]

12.0

TH

V

11.6

11.2

-25 0 25 50 75 100 125

Temperature [°C]

Figure 4. Start Threshold Voltage vs. Temp.

4.4

4.3

4.2

4.1

4.0

3.9

UVLO Hysteresis [V]

3.8

3.7

3.6

-25 0 25 50 75 100 125

Temperature [°C]

8.8

8.4

[V]

8.0

TL

V

7.6

7.2

-25 0 25 50 75 100 125

Temperature [°C]

Figure 5. Stop Threshold Voltage vs. Temp.

350

300

250

Ist [μA]

200

150

-25 0 25 50 75 100 125

Temperature [°C]

Figure 6. UVLO Hysteresis vs. Temp.

1.5

1.4

1.3

1.2

Iop [mA]

1.1

1.0

0.9

0.8

-25 0 25 50 75 100 125

Temperature [°C]

Figure 8. Operating Supply Current vs. Temp.

FAN7602B Rev. 1.0.0 6

Figure 7. Start-up Supply Current vs. Temp.

1.3

1.2

1.1

Istr [mA]

1.0

0.9

0.8

-25 0 25 50 75 100 125

Temperature [°C]

Figure 9. V

Star-up Current vs. Temp.

STR