Fairchild FAN7601 service manual

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FAN7601

Green Current Mode PWM Controller

www.fairchildsemi.com

Features

• Green Current Mode PWM Control

• Low Operating Current: Max 4mA

• Burst Mode Operation

• Internal High Voltage Start-up Switch

• Under Voltage Lockout (UVLO): 12V/8V

• Latch Protection & Soft Start Function

• Over Voltage Protection: 19V

• Operating Frequency up to 300kHz

• Max Duty Cycle: 95%

Typical Applications

• Off-Line Adapter Applications

• Auxiliary Power Supplies

Internal Block Diagram

Vref (10)

Rt/Ct

(5)

OSC4

Vref

12uA

5V Ref

Description

The FAN7601 is a green programmable frequency current mode PWM controller. It is specially designed for the off-line adapter application and the auxiliary power supplies which require high efficiency at a light load and no load. The internal high voltage start-up switch and the burst mode reduce the power loss. The FAN7601 includes some protections such as latch protection and over voltage protection. The latch protection can be used for over voltage protection and/or thermal protection and so on. And the soft start prevents the output voltage over shoot at start up.

Vstr (1)

Enable

10-SSOP

1

18

Start-up

Circuit

UVLO

8-SOP

1

OVP

12V/8V

19V

8-DIP

7

1

Vcc

(8)

Latch/SS

3

(4)

2.5V

1V

GND

5

(6)

* ( ) is 10-SSOP PIN Number

1.5V

OVP

Start-up

Circuit

R

S

R

Reset

Circuit

Q

Delay Circuit

0.97V/0.9V

Latch/SS

1V

6

2

OUT

(7)

CS/FB

(3)

S

Rev. 1.0.2

FAN7601

Pin Assignments

8-DIP, 8-SOP 10-SSOP

Vref Vcc Out GND

6 58 7

FAN7601

Vref Vcc Out GND

NC

9

7601

YWW

1 2

CS/FB Rt/CtLatch/SSVstr

3 4

1 2

NC

Pin Definitions

Pin Number Pin Name Pin Function Description

1 (1) Vstr Start-up

2 (3) CS/FB Current Sense and Feedback

3 (4) Latch/SS Latch Protection and Soft Start

4 (5) Rt/Ct Oscillator Timing

5 (6) GND Ground

6 (7) Out Gate Drive Output

7 (8) V

8 (10) V

*( ) is 10-SSOP PIN Number

CC

ref

IC Power Supply

Voltage Reference

3

CS/FB Rt/CtLatch/SSVstr

7 610 8

YWW

4 5

2

Absolute Maximum Ratings

(Ta = 25°C, unless otherwise specified)

Characteristics Symbol Value Unit

Supply Voltage V

Input Voltage CS/FB V

Operating Temperature T

Storage Temperature T

CC

CS/FB

OPR

STG

Junction Temperature Tj 150 °C

Output Current I

O

Vstr Input Voltage Vstr 500 V

ESD Capability, HBM Model (All pins except Vcc and Vstr)

-2.0kV

ESD Capability, Machine Model - 300 V

8-DIP

Thermal Resistance, Junction to Air

Rθja

10-SSOP 130

20 V

-0.3 to 20 V

-25 to +125 °C

-55 to +150 °C

250 mA

100

°C/W8-SOP 180

FAN7601

3

FAN7601

Electrical Characteristics

(Ta = -25°C ~ 125°C, Vcc = 14V, Rt = 9.5kΩ, Ct = 2.2nF unless otherwise specified)

Characteristics Symbol Conditions Min. Typ. Max. Unit

REFERENCE SECTION

Reference Output Voltage V

Line Regulation ∆V

Load Regulation ∆V

OSCILLATOR SECTION

Initial Accuracy F

OSC

Voltage Stability ST

Amplitude V

OCS

PWM SECTION

CS/FB Threshold Voltage1 V

Maximum Duty Cycle D

CS/FB1

MAX

Minimum Duty Cycle D

BURST MODE SECTION

CS/FB Threshold Voltage2

CS/FB Threshold Voltage3

(1)

V

CS/FB2

V

CS/FB3

SOFT START SECTION

Soft Start Current I

Soft Start Limit Voltage

(2)

V

PROTECTION SECTION

Latch Voltage V

Over Voltage Protection V

LATCH

OVP

UVLO SECTION

Start Threshold Voltage V

Minimum Operating Voltage V

TOTAL CURRENT SECTION

Operating Supply Current I

OUTPUT SECTION

Low Output Voltage V

High Output Voltage V

Rising Time

Falling Time

(1)

START UP SECTION

VSTR Start-up Current I

ref

ref1

ref2

MIN

SS

SL

tH

tL

OP

OL

OH

T

r

T

f

str

IO = 1mA 4.85 5.00 5.15 V

V

= 10V ~ 18V - 10 20 mV

CC

IO = 1mA ~ 10mA - 20 30 mV

- 90 100 110 kHz

V

= 10V ~ 18V - 1.0 1.5 %

CC

V

pin4 peak-to-peak

-1.25- V

- 0.9 1.0 1.1 V

Ta = 25°C929598%

---0%

-0.770.971.17V

- 0.7 0.9 1.1 V

V

= GND 9 12 15 µA

pin3

I

= 1µA 1.2 1.5 1.8 V

SS

- 2.25 2.5 2.75 V

-181920V

-111213V

-789V

--34mA

Ta =25°C, IO = 100mA - 2 2.5 V

Ta =25°C, IO = -100mA 11.5 12 14 V

Ta =25°C, CI = 1nF - 45 150 ns

Ta =25°C, CI = 1nF - 35 150 ns

V

= 30V, Ta =25°C 0.5 1 1.5 mA

str

Note:

1. These parameters, although guaranteed, are not 100% tested in production.

2. It is recommended to connect 1MΩ resistor between the Latch/SS pin and GND to prevent abnormal operation of the latch protection by noise coupling.

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