AP1520_技术文档

AP1520

PWM CONTROL 2A STEP-DOWN CONVERTER

General Description

Features

AP1520 consists of step-down switching regulator with PWM control.

These devices include a reference voltage source, oscillation circuit,

error amplifier, and internal PMOS.

•

Input Voltage: 3.6V to 23V

Output Voltage: 0.8V to V_CC

Duty Ratio: 0% to 100% PWM Control

Oscillation Frequency: 300KHz typ.

Soft-Start, Current Limit, Enable Function

Thermal Shutdown Function

Built-in Internal SW P-Channel MOS

SOP-8L Pb-Free Package

AP1520 provides low-ripple power, high efficiency, and excellent

transient characteristics. The PWM control circuit is able to vary the

duty ratio linearly from 0 up to 100%. This converter also contains

an error amplifier circuit as well as a soft-start circuit that prevents

overshooting at startup. An enable function, an over current

protect function and a short circuit protect function are built inside,

and when OCP or SCP happens, the operation frequency will be

reduced from 300KHz to 30KHz. Also, an internal compensation

block is built in to minimum external component count.

Lead Free Finish/RoHS Compliant (Note 1)

With the addition of an internal P-channel Power MOS, a coil,

capacitors, and a diode connected externally, these ICs can function

as step-down switching regulators. They serve as ideal power

supply units for portable devices when coupled with the SOP–8L

mini-package, providing such outstanding features as low current

consumption. Since this converter can accommodate an input

voltage up to 23V, it is also suitable for the operation via an AC

adapter.

Applications

•

PC Motherboard

LCD Monitor

Graphic Card

DVD-Video Player

Telecom Equipment

ADSL Modem

Printer and other Peripheral Equipment

Microprocessor Core Supply

Networking Power Supply

Ordering Information

AP1520 X X X

Packing

Lead-Free

Package

S: SOP-8L

-U : Tube

-13 : Taping

L : Lead-Free

Note: 1. RoHS revision 13.2.2003. Glass and High Temperature Solder Exemptions Applied, see EU Directive Annex Notes 5 and 7.

Tube

Part Number

13” Tape and Reel

Device

(Note 2)

Package

Code

Packaging

Quantity

Part Number

Suffix

-13

AP1520S

S

SOP-8L

100/Tube

-U

2500/Tape & Reel

Lead-free

Note: 2. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at

http://www.diodes.com/datasheets/ap02001.pdf.

AP1520 Rev. 1

1 of 8

JANUARY 2007

www.diodes.com

AP1520

PWM CONTROL 2A STEP-DOWN CONVERTER

Pin Descriptions

Pin Assignments

Name No.

( Top View )

Description

FB

EN

1

2

Feedback pin

Power-off pin

H: Normal operation

Vss

1

2

3

4

8

7

6

5

FB

(Step-down operation)

Vss

EN

OCSET

VCC

L: Step-down operation stopped

(All circuits deactivated)

Add an external resistor to set max

output current

IC power supply pin

Switch Pin. Connect external

AP1520

SOP-8L

Output

OCSET

V_CC

3

4

Output

Output 5, 6 inductor/diode here. Minimize trace

area at this pin to reduce EMI

7, 8 GND Pin

V_SS

Block Diagram

Output

Oscillation

Circuit

Reference Voltage

Source with Soft Start

V

cc

+

-

PWM-Switched

Control Circuit

FB

Thermal

Shutdown

100uA

V_EN

Vss

OCSET

EN

AP1520 Rev. 1

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JANUARY 2007

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AP1520

PWM CONTROL 2A STEP-DOWN CONVERTER

Absolute Maximum Ratings

Symbol

Parameter

Rating

Unit

V_CC

V_FB

V_EN

V_OUT

P_D

VCC Pin Voltage

Feedback Pin Voltage

EN Pin Voltage

Switch Pin Voltage

Power Dissipation

V_SS- 0.3 to V_SS+ 25

V_SS- 0.3 to V_CC

V_SS- 0.3 to V_IN+ 0.3

Internally limited

-20 to +85

V

mW

^oC

T_OPR

T_STG

Operating Temperature Range

Storage Temperature Range

-40 to +150

Caution: The absolute maximum ratings are rated values exceeding which the product could suffer physical damage. These values must

therefore not be exceeded under any conditions.

Electrical Characteristics ( VIN = 12V, T_a= 25°C, unless otherwise specified )

Symbol

Parameter

Input Voltage

Conditions

--

I_OUT= 0.1A

--

Min.

3.6

0.784

-

Typ.

-

0.8

0.1

-

Max. Unit

V_IN

23

0.816

0.5

-

V

µA

A

V_FBFeedback Voltage

I_FB

I_SW

Feedback Bias Current

Switch Current

2.5

Current Consumption

During Power off

I_SSS

V

_EN= 0V

-

10

1

-

µA

%

∆V_OUT

/V_OUT

∆V_OUT

/V_OUT

Line Regulation

Load Regulation

V_IN= 5V~23V

2

I_OUT= 0.1 to 2A

-

0.2

300

-

0.5

360

-

%

f_OSCOscillation Frequency

Measure waveform at SW pin

240

10

KHz

Frequency of Current Limit

or Short Circuit Protect

f_OSC1

V_SH

Evaluate oscillation at SW pin

Evaluate oscillation stop at SW pin

2.0

-

0.8

-

EN Pin Input Voltage

V_SL

V

I_SH

I_SL

EN Pin Input Leakage

Current

--

20

-10

90

1

110

70

µA

ms

-

I_OCSETOCSET Pin Bias Current

T_SSSoft-Start Time

75

0.3

-

105

2

150

100

--

V_IN= 5V, V_FB= 0V

V_IN= 12V, V_FB= 0V

V_IN= 12V, V_OUT= 5V

I_OUT= 2A

R_DSONInternal MOSFET R_DSON

EFFI Efficiency

mΩ

%

-

92

65

-

Thermal Resistance

θ_JA

^oC/W

Junction-to-Ambient

AP1520 Rev. 1

3 of 8

JANUARY 2007

www.diodes.com

AP1520

PWM CONTROL 2A STEP-DOWN CONVERTER

Typical Application Circuit

L1

V_IN

V_OUT

V

cc

Output

22uH

C_C

Optional

R_A

6.8K

R_OCSETC_OCSET

3K

AP1520

Option

+

-

+

FB

C_IN

OCSET

EN

C

C_OUT

0.1uF 470uF

680uF

V_SS

-

R_EN

100K

R_B

1.3K

CVcc

D1*

0.1uF

C_EN

0.1uF

Note: V_OUT= V_FBx (1+R_A/R_B)

R_B=0.7K~5K ohm

V_IN= 12V, I_MAX= 2A

V_OUT

L1 Value

2.5V

22uH

3.3V

27uH

5V

33uH

*D1 = Diodes Inc. part number DFLS230L or SBR3U30P1.

Typical Performance Characteristics

AP1520 Vin vs. Frequency

(Vout=3.3V; Iout=0.2A)

AP1520 Vin vs. FB

(Vout=3.3V; Iout=0.2A)

0.84

350

0.83

0.82

0.81

0.80

0.79

0.78

0.77

0.76

0.75

0.74

345

340

335

330

325

320

315

310

3.6

4

6

8

10 12 14 16 18

Vin (V)

3.6

4

6

8

10 12 14 16 18

Vin (V)

AP1520 Rev. 1

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JANUARY 2007

AP1520

PWM CONTROL 2A STEP-DOWN CONVERTER

Typical Performance Characteristics ( Continued )

AP1520 Load Regulation

(Vin=12V)

AP1520 Line Regulation

(Vin=12V; Iout=0.2A)

5.10

5.09

5.08

5.07

5.06

5.05

5.04

5.03

5.02

5.01

5.00

3.40

3.35

3.30

3.25

3.20

3.15

3.10

0.0

1.0

2.0

3.0

4.0

3.6

4

6

8

10 12 14 16 18

Vin (V)

Iout (A)

AP1520 Efficiency

100

90

80

70

60

50

40

30

20

10

0

Vout:5.0V

Vout:3.3V

0.0

0.5

1.0

1.5

2.0

Iout (A)

AP1520 Vout Ripple

( V_in= 12V; V_out= 3.3V; I_out= 0.1A )

AP1520 Vout Ripple

( V_in= 12V; V_out= 3.3V; I_out= 2A )

AP1520 Rev. 1

5 of 8

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JANUARY 2007

AP1520

PWM CONTROL 2A STEP-DOWN CONVERTER

Test Circuit

open

OUTPUT

open

OUTPUT

A

FB

V_CC

OCSET

EN

+

-

OCSET

EN

A

V_SS

V

SS

OUTPUT

FB

V_CC

OCSET

EN

+

-

V

+

-

V_SS

Function Description

PWM Control

resumes once V_CCrises above 3.5V.

The AP1520 consists of DC/DC converters that employ a

Pulse-Width Modulation (PWM) system. In converters of the

AP1520, the pulse width varies in a range from 0 to 100%,

according to the load current. The ripple voltage produced by the

switching can easily be removed through a filter because the

switching frequency remains constant. Therefore, these

converters provide a low-ripple power over broad ranges of input

voltage and load current.

R_DS(ON)Current Limiting

The current limit threshold is setting by the external

resistor connecting from V_CCsupply to OCSET. The internal

100uA sink current crossing the resistor sets the voltage at the

pin of OCSET. When the PWM voltage is less than the voltage at

OCSET, an over-current condition is triggered.

×

=

×

I_LOADR_DS(ON)I_OCSETR_OCSET

Under Voltage Lockout

See above formula for setting the current limit value.

The Under Voltage Lockout circuit of the AP1520 assures

that the high-side MOSFET driver outputs remain in the off state

whenever the supply voltage drops below 3.3V. Normal operation

AP1520 Rev. 1

6 of 8

www.diodes.com

JANUARY 2007

AP1520

PWM CONTROL 2A STEP-DOWN CONVERTER

Marking Information

(1) SOP-8L

( Top View )

8

5

4

Logo

Part no.

AP1520

YY WW X

ID code: internal

Xth week: 01~52

Year: "01" =2001

"02" =2002

1

Device

AP1520S

Package

SOP-8L

Identification Code

AP1520

Package Information ( All Dimensions in mm )

Package Type: SOP-8L

Gauge Plane

Seating Plane

0.38/1.27

Detail "A"

7°~9°

0.35max.

45°

Detail "A"

0.3/0.5

3.70/4.10

1.27typ

4.80/5.30

AP1520 Rev. 1

7 of 8

www.diodes.com

JANUARY 2007

AP1520

PWM CONTROL 2A STEP-DOWN CONVERTER

IMPORTANT NOTICE

Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further

notice to any product herein. Diodes Incorporated does not assume any liability arising out of the application or use of any product described herein; neither

does it convey any license under its patent rights, nor the rights of others. The user of products in such applications shall assume all risks of such use and will

agreeto hold DiodesIncorporatedand all the companieswhose productsare represented onour website, harmlessagainst all damages.

LIFE SUPPORT

Diodes Incorporated productsare notauthorizedfor use ascriticalcomponentsin lifesupportdevices or systemswithout theexpressed written approval ofthe

PresidentofDiodesIncorporated.

AP1520 Rev. 1

8 of 8

JANUARY 2007

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型号：	AP1520
厂家：	DIODES INCORPORATED
描述：	PWM CONTROL 2A STEP-DOWN CONVERTER PWM控制2A降压转换器转换器
文件：	总8页 (文件大小：256K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

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