Datasheet AP5724FDCG, AP5724WG, AP5724WUG Datasheet (Diodes)

A

Pb

P5724

WHITE LED STEP-UP CONVERTER

Description

The AP5724 is a step-up DC/DC converter specifically designed to

drive white LEDs with a constant current. The device can drive 2 ~ 6

LEDs in series from a Li-Ion cell. Series connection of the LEDs

provides identical LED currents resulting in uniform brightness and

eliminates the need for ballast resistors. For driving higher number of

LEDs, AP5724 also supports a single feedback of parallel connected

multiple strings of equal number of LEDs.

The AP5724 switches at 1.2MHz that allows the use of tiny external

components. A low 0.1V feedback voltage minimizes power loss in

the current setting resistor for better efficiency

Pin Assignments

(Top View)

1

SW

2

GND

3

FB

SOT26 / TSOT23-6

(Top View)

VIN

6

5

OVP

7

4

EN

Features

1

• High Efficiency: 84% Typical

• Fast 1.2MHz Switching Frequency

• Current Limit and UVLO Protections

• Internal Thermal Shutdown

• Internal Over Voltage Protection

• Integrated Soft-Start Function

• SOT26, TSOT26 and U-DFN2020-6: Available in “Green”

Molding Compound (No Br, Sb)

• Lead-Free Finish; RoHS Compliant (Notes 1 & 2)

Notes: 1. EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. All applicable RoHS exemptions applied.

2. See http://www.diodes.com/quality/lead_free.html for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green" and Lead-free.

Applications

• Cellular Phones

• PDAs, Hand held Computers

• Digital Cameras

• MP3 Players

• GPS Receivers

SW

2

V

IN

OVP

3

U-DFN2020-6

6

GND

5

FB

4

EN

Typical Applications Circuit

V

IN

OFFON

PWM Dimming

AP5724

Document number: DS31843 Rev. 4 - 2

C

1uF

L1

22uH

IN

V

IN

AP5724

EN

D1

SW

OVP

FB

GND

Figure 1 Typical Application Circuit

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R

SET

5

2~6 LEDs

C

OUT

1uF

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Pin Descriptions

Pin Name Functions

SW Switch Pin. Connect inductor/diode here. Minimize trace area at this pin to reduce EMI.

GND GND pin.

FB

EN

OVP Output Voltage detect pin for over voltage protection.

VIN

Feedback Pin. Reference voltage is 0.1V. Connect cathode of lowest LED and a sense resister here. Calculate resistor value according to the formula: R

Converter On/Off Control Input. A high input at EN turns the converter On, and a low input turns it off. If On/Off control is not needed, connect EN to the input source for automatic startup. The EN pin cannot be left floating.

Input Supply Pin. Must be locally bypassed with 1μF or 2.2μF to reduce input noise.

= 0.1V / ILED

SET

Functional Block Diagram

P5724

OVP

5

1

Comparator

-

A2

+

Rc

A1

-

+

FB

3

V

6

IN

REF

0.1V

Cc

Σ

OTP

CONTROL

LOGIC

Driver

+

SW

Q1

-

RAMP

Generator

4

EN

Absolute Maximum Ratings (@T

Symbol Parameter Rating Unit

VIN

VSW SW Voltage -0.3 to +34 V

V

OVP

VFB

EN EN -0.3 to +7 V

T

J(MAX)

T

LEAD

T

ST

Caution: Operation above the absolute maximum ratings can cause device failure. These values, therefore, must not be exceeded under any condition.

AP5724

Document number: DS31843 Rev. 4 - 2

Operation at the absolute maximum rating for extended periods, may reduce device reliability.

Enable

1.2MHz

Oscillator

= +25°C, unless otherwise specified.)

A

VIN Pin Voltage -0.3 to +7 V

OVP Pin Voltage -0.3 to +35 V

Feedback Pin Voltage -0.3 to +7 V

Maximum Junction Temperature 150 °C

Lead Temperature 300 °C

Storage Temperature Range -65 to +150 °C

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2

GND

December 2013

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P5724

Recommended Operating Conditions (@T

Symbol Parameter Min Max Unit

VIN

TJ

TA

Electrical Characteristics (@ V

Symbol Parameter Conditions Min Typ Max Unit

System Supply Input

VIN

UVLO Under Voltage Lockout — 2.2 2.4 V

Under Voltage Lockout Hysteretic — 85 — mV

IQ

ISD

Oscillator

F

OSC

Dmax Maximum Duty Cycle 86 90 — %

Reference Voltage

VFB

IFB

MOSFET

Rds(on) On Resistance of MOSFET — 0.95 1.2 Ω

I

OCP

Control and Protection

EN Voltage High ON 1.5 — — V EN Voltage Low OFF — — 0.4 V

IEN

OVP OVP Threshold 26 30 34 V

θJA

θJC

Note: 3. Test condition for SOT26, TSOT26 and U-DFN2020-6: Device mounted on FR-4 substrate, single-layer PC board, 2oz copper, with minimum recommended pad layout

AP5724

Document number: DS31843 Rev. 4 - 2

Input Voltage 2.7 5.5 V

Operating Junction Temperature -40 125 °C

Operating Ambient Temperature -40 85 °C

= 3.6V, TA = +25°C, unless otherwise specified.)

IN

Operating Input Voltage 2.7 — 5.5 V

Quiescent Current FB = 0.2V, No Switching — 500 — μA

Shutdown Current

Operation Frequency 1 1.2 1.4 MHz

Feedback Voltage 0.09 0.1 0.11 V

FB Pin Bias Current 10 45 100 nA

Switching Current Limit Normal Operation — 750 — mA

EN Pin Pull Low Current — 4 6 μA

Thermal Resistance Junction-to-Ambient

Thermal Resistance Junction-to-Case

= +25°C, unless otherwise specified.)

A

VEN < 0.4V

SOT26 (Note 3) — 162 —

U-DFN2020-6 (Note 3) — 200 —

SOT26 (Note 3) — 36 —

TSOT26 (Note 3) — 32 —

U-DFN2020-6 (Note 3) — 30 —

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— 0.1 1 μA

°C/W TSOT26 (Note 3) — 152 —

°C/W

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Typical Performance Characteristics (6 LEDS, V

= 3.6V, I

IN

= 25mA)

OUT

P5724

VIN vs. Shutdown Current

1

0.8

0.6

0.4

0.2

Shutdown Current(uA)

0

2.5 3 3.5 4 4.5 5 5.5

V

(V)

IN

VIN vs. Frequency

1.25

1.2

1.15

1.1

Frequency(MHz)

1.05

V

vs. Quiescent Current

IN

700

600

500

400

300

200

100

Quiescent Current(uA)

0

2.5 3 3.5 4 4.5 5 5.5

100

95

90

Max Duty(%)

85

V

(V)

IN

VIN vs. Max Duty

1

2.5 3 3.5 4 4.5 5 5.5

VIN vs. Feedback Voltage

0.12

0.11

0.1

0.09

0.08

Feedback Voltage(V)

0.07

0.06

2.5 3 3.5 4 4.5 5 5.5

AP5724

Document number: DS31843 Rev. 4 - 2

80

V

(V)

IN

(V)

V

IN

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2.533.544.555.5

(V)

V

IN

I

vs. Feedback Voltage

OUT

0.12

0.11

0.1

0.09

0.08

0.07

Feedback Voltage(V)

0.06 0 1020304050

I

OUT

(mA)

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Typical Performance Characteristics (cont.) (6 LEDS, V

= 3.6V, I

IN

= 25mA)

OUT

P5724

VIN vs. OVP Threshold

35

33

31

29

27

OVP Threshold(V)

25

2.5 3 3. 5 4 4. 5 5 5.5

(V)

V

IN

Temperature vs. OVP Threshold

35

30

25

20

Temperature vs. Shutdown Current

1

0.8

0.6

0.4

0.2

Shutdown Current(uA)

0

-50 -25 0 25 50 75 100 125

Temperature (℃)

Tem perature vs. Frequency

1.7

VIN = 4.2V

1.4

1.1

0.8

VIN = 3.6V

OVP Threshold(V)

15

10

-50 -25 0 25 50 75 100 125

Temperature vs. Feedback Voltage

120

110

100

90

80

Feedback Voltage(mV)

70

60

-50 -25 0 25 50 75 100 125

AP5724

Document number: DS31843 Rev. 4 - 2

Temperature (℃)

VIN = 4.2V

VIN = 3.6V

Temperature (℃)

Frequency (MHZ)

0.5

0.2

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-50 -25 0 25 50 75 100 125

Temperature (℃)

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Typical Performance Characteristics (cont.) (6 LEDS, V

I

vs. Efficie ncy

OUT

90

= 3.6V, I

IN

90

= 25mA)

OUT

I

vs. Efficiency

OUT

P5724

85

80

75

70

Efficiency(%)

65

4 LEDs ; L = 22uH

60

0 5 10 15 20 25 30

100

90

80

70

60

Efficiency(%)

50

3 LEDs

V

= 4.2V

VIN = 3.6V

(mA)

I

OUT

V

vs. Efficiency

IN

4 LEDs

6 LEDs

85

80

75

70

Efficiency(%)

65

VIN = 4.2V

VIN = 3.6V

6 LEDs ; L = 22uH

60

0 5 10 15 20 25 30

I

OUT

(mA)

40

2.5 3 3.5 4 4.5 5

AP5724

Document number: DS31843 Rev. 4 - 2

VIN (V)

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Typical Performance Characteristics (cont.) (6 LEDS, V

Ripple

V

= 3.6V; 4 LEDs ; I

V

IN

OUT

= 30mA

= 3.6V, I

IN

= 25mA)

OUT

= 3.6V; 6 LEDs ; I

V

IN

V

OUT

Ripple

= 30mA

OUT

P5724

SW SW

POWER ON

= 3.6V; 6 LEDs ; I

V

IN

VOUT

POWER OFF

OUT

= 30mA

VIN = 3.6V; 6 LEDs ; I

= 30mA

OUT

VEN

VOUT

Irushi

VOUT

VEN

VOUT

Irushin

AP5724

Document number: DS31843 Rev. 4 - 2

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P5724

Applications Information

Inductor Selection

A 10μH to 22μH inductor is recommended for most AP5724 applications. For high efficiency the inductor should have low core losses at 1.2MHz

and low DCR (copper wire resistance). The inductor saturation current rating should also exceed the peak input current, especially for high load

current applications (like 3S8P).

Capacitor Selection

The small size of the ceramic capacitors are ideal for AP5724 applications. X5R and X7R types are recommended because they retain their

capacitance over wider voltage and temperature ranges than other types such as Y5V or Z5U. A 1μF input capacitor and a 1μF output capacitor

are sufficient for most AP5724 applications. For high output current applications like 3S8P, larger output capacitor of 2.2µF to 4.7µF is

recommended to minimize output ripple.

Diode Selection

Schottky diodes, with their low forward voltage drop and fast reverse recovery, are the ideal choices for AP5724 applications. The forward voltage

drop of a Schottky diode represents the conduction losses in the diode, while the diode capacitance (C

For diode selection, both forward voltage drop and diode capacitance need to be considered. Schottky diodes with higher current ratings usually

have lower forward voltage drop and larger diode capacitance, which can cause significant switching losses at the 1.2MHz switching frequency of

the AP5724. Schottky diodes with higher current ratings usually have lower forward voltage drop and larger diode capacitance. Larger Schottky

diode capacitance can cause significant switching losses at the 1.2MHz switching frequency of the AP5724. A Schottky diode rated at 100mA to

200mA is sufficient for most AP5724 applications.

LED Current Control

The LED current is controlled by the feedback resistor (R

to have accurate LED current, precision resistors are preferred (1% is recommended). The formula and table for R

= 0.1V/I

R

SET

Table 1. R

(mA) R

I

LED

5 20

10 10

15 6.6

20 5

30 3.3

40 2.5

(See Table 1)

LED

Resistor Value Selection

SET

(Ω)

SET

in Figure 1). The feedback reference is 0.1V. The LED current is 0.1V/ R

SET

Open-Circuit Protection

In the cases of output open circuit, when the LEDs are disconnected from the circuit or the LEDs fail, the feedback voltage will be zero. The AP5724

will then switch at a high duty cycle resulting in a high output voltage, which may cause the SW and OVP pin voltage to exceed the voltage rating of

these pins. The OVP pin monitors the output voltage. If the output voltage reaches the over voltage protection threshold at the OVP pin (Figure 2),

the over voltage protection is activated and SW pin stops switching.

L1

V

IN

C

IN

22uH

D1

1uF

or CD) represents the switching losses.

T

. In order

SET

selection are shown below.

SET

C

OUT

1uF

AP5724

Document number: DS31843 Rev. 4 - 2

V

IN

AP5724

EN

Figure 2 LED Driver with Open-Circuit Protection

SW

OVP

GND

www.diodes.com

x

FB

RSET

5

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P5724

Applications Information (cont.)

Dimming Control

There are four different types of dimming control circuits:

1. Using a PWM Signal to EN Pin

With the PWM signal applied to the EN pin, the AP5724 is turned on or off by the PWM signal. The LEDs operate at either zero or full current. The

average LED current increases proportionally with the duty cycle of the PWM signal. A 0% duty cycle will turn off the AP5724 and corresponds to

zero LED current. A 100% duty cycle corresponds to full current. The typical frequency range of the PWM signal is below 2 kHz.

2. Using a DC Voltage

For some applications, the preferred method of brightness control is a variable DC voltage to adjust the LED current. The dimming control using a

DC voltage is shown in Figure 3. As the DC voltage increases, the voltage drop on R2 increases and the voltage drop on R

the LED current decreases. The selection of R2 and R3 will make the current from the variable DC source much smaller than the LED current and

much larger than the FB pin bias current. For V

from 0mA to 20mA.

range from 0V to 2V, the selection of resistors in Figure 3 gives dimming control of LED current

DC

decreases. Thus,

SET

AP5724

FB

R3

100k

V

DC

R2 5k

RSET

5

3. Using a Filtered PWM Signal

The filtered PWM signal can be considered as an adjustable DC voltage. It can be used to replace the variable DC voltage source in dimming

control.

4. Using a Logic Signal

For applications that need to adjust the LED current in discrete steps, a logic signal can be used as shown in Figure 4. R

current (when the NMOS is off). R

sets how much the LED current increases when the NMOS is turned on.

SET

Figure 3 Dimming Control Using a DC Voltage

sets the minimum LED

SET

AP5724

Document number: DS31843 Rev. 4 - 2

FB

RINC

Logic

RSET

Signal

Figure 4 Dimming Control Using a Logic Signal

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Applications Information (cont.)

C1 1uF

D2

D3

D4

D5

D6

LED

D1 B0540WS

R1 5ohm

1

2

3

L1 22uH

U1

SW

GND

FB

AP5724

OVP

P5724

VINVOUT

C2 1uF

6

Vin

5

4

EN

ON OFF

D7

LED

Table 2. Suggested Inductors

Vendor

Inductors

(µH)

Current Rating

(A)

Type

Dimensions

(mm)

Wurth Electronics 22 0.51A SMD 3.8X 3.8 X 1.6 744031220

GOTREND 22 0.56A SMD 3.8 X 3.8 X 1.05 GLP3810PH220N

TAIYO YUDRN 22 0.51A SMD 4.0 X 4.0 X 1.25 NR4012

Table 3. Suggested Capacitors for C

IN

and C

OUT

Vendor Capacitance Type Series

TAIYO YUDEN 1µF SMD TMK212 B7105MG-T

Table 4. Suggested Diodes

Vendor Rating Type Series

ZETEX 40V/0.5A SOD323 ZLLS400

DIODES 40V/0.5A SOD323 B0540WS

DIODES 40V/0.25A SOD523 SDM20U40

Table 5. Suggested Resistor

Vendor Type Series

YAGEO SMD FR-SK

Table 6. Suggested W-LED

Vendor Type Series

LITEON SMD LTW-C1911UC5

Series

AP5724

Document number: DS31843 Rev. 4 - 2

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Ordering Information

P5724

AP 5724 XXX G - 7

Package

W : SOT26

WU : TSOT26

FDC : U-DFN2020-6

Green

G : Green

Packing

7 : Tape & Reel

Part Number Package Code Packaging

AP5724WG-7 W SOT26 3000/Tape & Reel -7

AP5724WUG-7 WU TSOT26 3000/Tape & Reel -7

AP5724FDCG-7 FDC U-DFN2020-6 3000/Tape & Reel -7

Quantity Part Number Suffix

7” Tape and Reel

Marking Information

(1) SOT26 and TSOT26

( Top View )

6

5

7

4

XX : Identification Code

: Year 0~9

XX Y

WX

Y

W : Week : A~Z : 1~26 week;

a~z : 27~52 week; z represents

1 2 3

52 and 53 week

X

: A~Z : Green

Part Number Package Identification Code

AP5724WG-7 SOT26 FB

AP5724WUG-7 TSOT26 GB

(2) U-DFN2020-6

AP5724

Document number: DS31843 Rev. 4 - 2

( Top View )

XX

: Identification Code

XX

Y W X

Part Number Package Identification Code

AP5724FDCG-7 U-DFN2020-6 GB

www.diodes.com

Y : Year : 0~9

W

: Week : A~Z : 1~26 week;

a~z : 27~52 week; z represents

52 and 53 week

X

: A~Z : Green

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December 2013

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θ

Package Outline Dimensions (All dimensions in mm.)

Please see AP02002 at http://www.diodes.com/datasheets/ap02002.pdf for latest version.

(1) SOT26

A

K

J

H

B C

M

D

L

(2) TSOT26

E1

A2

A

A1

D

e1

E

c

L

4x 1

e

6x b

θ

L2

(3) U-DFN2020-6 Type C

A1

A

Pin #1 ID

E

E2

Z (4x)

AP5724

Document number: DS31843 Rev. 4 - 2

D

D2

e

b

A3

Seating Plane

L

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Dim Min Max Typ

SOT26

A 0.35 0.50 0.38 B 1.50 1.70 1.60 C 2.70 3.00 2.80 D

⎯ ⎯

H 2.90 3.10 3.00 J 0.013 0.10 0.05 K 1.00 1.30 1.10 L 0.35 0.55 0.40 M 0.10 0.20 0.15

0° 8°

α

All Dimensions in mm

TSOT26

Dim Min Max Typ

A

−

A1 0.01 0.10 A2 0.84 0.90

D

− −

E

− −

E1

− −

b 0.30 0.45 c 0.12 0.20 e

− −

e1

− −

L 0.30 0.50

L2

− −

θ 0° 8° 4°

θ1 4° 12°

All Dimensions in mm

U-DFN2020-6

Dim Min Max Typ

Type C

A 0.57 0.63 A1 0.00 0.05 A3 –– ––

b 0.25 0.35 0.30

D 1.95 2.075 2.00 D2 1.55 1.75 1.65

E 1.95 2.075 2.00

E2 0.86 1.06 0.96

e –– –– L 0.25 0.35 0.30

–– ––

Z

All Dimensions in mm

1.00

0.95

⎯

−

2.90

2.80

1.60

−

0.95

1.90

0.25

−

0.60

0.02

0.15

0.65

0.20

P5724

December 2013

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Suggested Pad Layout

Please see AP02001 at http://www.diodes.com/datasheets/ap02001.pdf for the latest version.

(1) SOT26

G

Z

Y

X

C2

C1

Dimensions Value (in mm)

Z G X Y

C1 2.40

C2

(2) TSOT26

C C

Y1

(3) U-DFN2020-6 Type C

AP5724

Document number: DS31843 Rev. 4 - 2

Y2

Y (6x)

X (6x)

X2

X1

Y(6x)

Y1

X (6x) C

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Dimensions Value (in mm)

C X Y

Y1

Dimensions

C 0.650

X 0.350 X1 1.650 X2 1.700

Y 0.525 Y1 1.010 Y2 2.400

3.20

1.60

0.55

0.80

0.95

0.950

0.700

1.000

3.199

Value

(in mm)

P5724

December 2013

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Tape Orientation

For U-DFN2020-6

P5724

Note: 4. The taping orientation of the other package type can be found on our website at http://www.diodes.com/datasheets/ap02007.pdf.

AP5724

Document number: DS31843 Rev. 4 - 2

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P5724

DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).

Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability arising out of the application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its patent or trademark rights, nor the rights of others. Any Customer or user of this document or products described herein in such applications shall assume all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on Diodes Incorporated website, harmless against all damages.

Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized sales channel. Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall indemnify and hold Diodes Incorporated and its representatives harmless against all claims, damages, expenses, and attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.

Products described herein may be covered by one or more United States, international or foreign patents pending. Product names and markings noted herein may also be covered by one or more United States, international or foreign trademarks.

This document is written in English but may be translated into multiple languages for reference. Only the English version of this document is the final and determinative format released by Diodes Incorporated.

Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:

A. Life support devices or systems are devices or systems which:

1. are intended to implant into the body, or

2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the

labeling can be reasonably expected to result in significant injury to the user.

B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or to affect its safety or effectiveness.

Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-related information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems.

www.diodes.com

IMPORTANT NOTICE

LIFE SUPPORT

AP5724

Document number: DS31843 Rev. 4 - 2

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December 2013

Datasheet AP5724FDCG, AP5724WG, AP5724WUG Datasheet (Diodes) [ru]

Specifications and Main Features

Frequently Asked Questions

User Manual