SW 1 6 VIN AP3019A - Diodes Incorporated · WHITE LED STEP-UP CONVERTER 5 Description The AP3019A is an inductor-based DC/DC converter designed to drive ... Uses Tiny 1mm Tall Inductor

AP3019A Document number: DS41298 Rev. 3 - 2

1 of 12 www.diodes.com

August 2018 © Diodes Incorporated

AP3019A

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WHITE LED STEP-UP CONVERTER

Description

The AP3019A is an inductor-based DC/DC converter designed to

drive up to eight white LEDs in series for backlight. Only one

feedback resistor is needed to control the LED current and obtain

required brightness.

A constant frequency 1.2MHz PWM control scheme is employed in

this IC, which means tiny external components can be used.

Specifically, 1mm tall inductor and 0.22F output capacitor for a

typical application is sufficient. Additionally, the Schottky diode in

boost circuit is integrated on this chip. The AP3019A also provides a

disable pin to ease its use for different systems.

The output over-voltage protection is implemented in AP3019A. When

any LED is broken or in other abnormal conditions, the output voltage

will be clamped.

The AP3019A is available in standard SOT-23-6 and TSOT-23-6

packages.

Features

Inherently Uniform LED Current

High Efficiency up to 84%

No Need for External Schottky Diode

Output Over-voltage Protection (OVP)

Fixed 1.2MHz Switching Frequency

Uses Tiny 1mm Tall Inductor

Requires only 0.22F Output Capacitor

Pin Assignments

(Top View)

1

2

3 4

5

Pin 1 Mark

6SW

GND

FB CTRL

VIN

VOUT

K/KT Package

(SOT-23-6/TSOT-23-6)

Applications

Cellular Phones

Digital Cameras

LCD Modules

GPS Receivers

PDAs, Handheld Computers

http://www.diodes.com




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Typical Applications Circuit

22 H

1F

0.22F

10

VIN

SW VOUT

FBGND

CTRL

AP3019AControlSignal

VIN

3V L

CIN

COUT

1

6

4

5

2

3

C: X5R or X7R dielectric

L: SUMIDA CDRH5D28R-220NC or equivalent

This circuit can work in full temperature

Pin Descriptions

Pin Number Pin Name Function

1 SW Switch pin. Connect external inductor

2 GND Ground

3 FB Voltage feedback pin. Reference voltage is 200mV

4 CTRL Shutdown and dimming pin. Connect to 1.8V or higher to enable device; Connect to 0.5V or less to disable device; Connect to a PWM signal to achieve LEDs brightness dimming

5 VOUT Output pin. Connect to the cathode of internal Schottky diode

6 VIN Input supply pin. Must be connected to a local bypass capacitor





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Functional Block Diagram

Q1A2

A1R

S

Q

1.2 MHz

OSCILLATOR

RAMP

GENERATOR

VREF

3

6

4

2

5

DRIVER

1.25 V

COMPARATOR

OVP

200mV

1

SOFT

START

FB SW

VOUT

GND

CTRL

VIN

Absolute Maximum Ratings (Note 1)

Note 1. Stresses greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and

functional operation of the device at these or any other conditions beyond those indicated under “Recommended Operating Conditions” is not implied. Exposure to “Absolute Maximum Ratings” for extended periods may affect device reliability.

Symbol Parameter Rating Unit

VIN Input Voltage 20 V

VSW SW Pin Voltage 38 V

VFB Feedback Voltage 20 V

VCTRL CTRL Pin Voltage 20 V

JA Thermal Resistance (Junction to Ambient, No Heat Sink) 265 C/W

TJ Operating Junction Temperature +150 C

TSTG Storage Temperature Range -65 to +150 C

TLEAD Lead Temperature (Soldering, 10sec) +260 C

– ESD (Machine Model) 250 V

– ESD (Human Body Model) 2000 V





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Recommended Operating Conditions

Symbol Parameter Min Max Unit

TOP Operating Temperature Range -40 +85 C

VIN Input Voltage 2.5 16 V

VCTRL CTRL Pin Voltage – 16 V

Electrical Characteristics (@VIN =3V, VCTRL=3V, TA =+25°C, unless otherwise specified.)

Symbol Parameter Condition Min Typ Max Unit

VIN (MIN) Minimum Operating Voltage – 2.5 – – V

VIN (MAX) Maximum Operating Voltage – – – 16

VFB Feedback Voltage (Note 2) IOUT=20mA, 4 LEDs, TA=-40oC to +85

oC 188 200 212 mV

IFB FB Pin Bias Current – – 35 100 nA

IQ Quiescent Current VFB=VIN, No Switching 1.5 2.5 3.2 mA

ISHDN Shutdown Quiescent Current VCTRL=0V 2.0 4.0 6.0 A

f Switching Frequency – 0.9 1.2 1.5 MHz

DMAX Maximum Duty Cycle – 90 93 – %

ILIMIT Switch Current Limit (Note 3) D=40% – 550 –

mA D=80% – 550 –

VCESAT Switch VCE Saturation Voltage ISW=250mA – 360 – mV

– Switch Leakage Current VSW=5V – 0.01 5 A

VCTRL CTRL Pin Voltage High 1.8 – –

V Low – – 0.5

ICTRL CTRL Pin Bias Current – – 100 – A

VOV OVP Voltage – – 30 – V

VDROP Schottky Forward Drop ID=150mA – 0.7 – V

– Schottky Leakage Current VR(Reverse Voltage)=23V – 0.1 4

A VR(Reverse Voltage)=27V – – 150

t Soft Start Time – – 300 – s

JC Thermal Resistance

(Junction to Case)

SOT-23-6 – 60 – C/W

TSOT-23-6 – 60 –

Notes: 2. The bold type specifications of full temperature range are guaranteed by design (GBD).

3. The switch current limit is related to duty cycle. Please refer to Figure Current Limit vs. Duty Cycle for detail.





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Performance Characteristics (WLED forward voltage (VF) is 3.45V at IF=20mA, unless otherwise noted.)

Efficiency vs. Junction Temperature Efficiency vs. Input Voltage

Efficiency vs. LED’s Number Schottky Forward Current vs. Schottky Forward Drop

Shutdown Quiescent Current vs. Input Voltage Quiescent Current vs. Input Voltage

-50 -25 0 25 50 75 10073

74

75

76

77

78

79

80

81

82

83

VIN

=3.6V, IOUT

=20mA, 8 LEDs

CIN

=1F, COUT

=0.22F, L=22H

E

ffic

ien

cy (

%)

Junction Temperature (oC)

3.0 3.5 4.0 4.5 5.070

72

74

76

78

80

82

84

86

IOUT

=20mA, 8 LEDs,TA=+25

OC

CIN

=1F, COUT

=0.22F, L=22H

Eff

icie

ncy (

%)

Input Voltage (V)

2 3 4 5 6 7 876

77

78

79

80

81

82

83

84

85

86

VIN

=3.6V, IOUT

=20mA,TA=+25

OC

CIN

=1F, COUT

=0.22F, L=22H

LED's Number

Eff

icie

ncy (

%)

0 200 400 600 800 10000

50

100

150

200

250

300

350

S

ch

ottky F

orw

ard

Cu

rre

nt (m

A)

Schottky Forward Drop (mV)

2 4 6 8 10 12 14 160

5

10

15

20

25

30

Sh

utd

ow

n Q

uie

sce

nt C

urr

en

t (

A)

Input Voltage (V)

TA=+25

OC

0 2 4 6 8 10 12 14 160.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Qu

iesce

nt C

urr

en

t (m

A)

Input Voltage (V)

TA=-50

OC

TA=+25

OC

TA=+100

OC





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Performance Characteristics (WLED forward voltage (VF) is 3.45V at IF=20mA, unless otherwise noted.) (Cont.)

Input Current in Output Open Circuit vs. Input Voltage Frequency vs. Junction Temperature

Feedback Voltage vs. Junction Temperature Schottky Forward Drop vs. Junction Temperature

Schottky Leakage Current vs. Junction Temperature Current Limit vs. Duty Cycle

-50 -25 0 25 50 75 1000.90

0.95

1.00

1.05

1.10

1.15

1.20

1.25

1.30

1.35

1.40

Fre

qu

en

cy (

MH

z)


2.5 3.0 3.5 4.0 4.5 5.02.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

Inp

ut C

urr

en

t (m

A)

Input Voltage (V)

-50 -25 0 25 50 75 100190

192

194

196

198

200

202

204

206

208

210

Fe

ed

ba

ck V

olta

ge

(m

V)


-50 -25 0 25 50 75 1000.60

0.62

0.64

0.66

0.68

0.70

0.72

0.74

0.76

0.78

0.80

S

cho

ttky F

orw

ard

Dro

p (

V)


ID=150mA

-50 -25 0 25 50 75 1000.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

Scho

ttky L

ea

ka

ge

Cu

rre

nt (

A)


VR=10V

VR=16V

VR=23V

30 40 50 60 70 80 90100

200

300

400

500

600

700

-50OC

+25OC

+100OC

Cu

rre

nt L

imit

(mA

)

Duty Cycle (%)





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LED

1 I

mV200R =

Performance Characteristics (WLED forward voltage (VF) is 3.45V at IF=20mA, unless otherwise noted.) (Cont.)

Saturation Voltage vs. Switch Current CTRL Pin Voltage vs. Junction Temperature

Application Information

Operation

The AP3019A is a boost DC-DC converter which uses a constant frequency, current mode control scheme to provide excellent line and load

regulation. Operation can be best understood by referring to the Figure Functional Block Diagram of AP3019A.

At the start of each oscillator cycle, the SR latch is set and switch Q1 turns on. The switch current will increase linearly. The voltage on sense

resistor is proportional to the switch current. The output of the current sense amplifier is added to a stabilizing ramp and the result is fed into the

non-inversion input of the PWM comparator A2. When this voltage exceeds the output voltage level of the error amplifier A1, the SR latch is reset

and the switch is turned off.

It is clear that the voltage level at inversion input of A2 sets the peak current level to keep the output in regulation. This voltage level is the output

signal of error amplifier A1, and is the amplified signal of the voltage difference between feedback voltage and reference voltage of 200mV. So, a

constant output current can be provided by this operation mode.

L1

C1

C2

R1

VIN

SW VOUT

FBGND

CTRL

AP3019AControl

Signal

VIN

3V

1

6

4

5

2

3

Typical Application Circuit to Decide R1

LED Current Control

Refer to Figure Typical Application Circuit to Decide R1, the LED current is controlled by the feedback resistor R1. LEDs' current accuracy is

determined by the regulator's feedback threshold accuracy and is independent of the LED's forward voltage variation. So the precise resistors are

preferred. The resistance of R1 is in inverse proportion to the LED current since the feedback reference is fixed at 200mV. The relation for R1 and

LED current can be expressed as below:

50 100 150 200 250 30050

100

150

200

250

300

350

400

450

Sa

tura

tio

n V

olta

ge

(m

V)

Switch Current (mA)

-50 -25 0 25 50 75 1000.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

CT

RL

Pin

Vo

lta

ge

(V

)

Junction Temperature (OC)

Falling Edge

Rising Edge





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Application Information (Cont.)

Over Voltage Protection

The AP3019A has an internal open-circuit protection circuit. When the LEDs are disconnected from circuit or fail open, the output voltage is

clamped. The AP3019A will switch at a low frequency, and minimize input current.

Soft Start

The AP3019A has an internal soft start circuit to limit the inrush current during startup. The time of startup is controlled by internal soft start

capacitor. Please refer to Figure Soft Start Waveform.

IIN100mA/div

VOUT5V/div

VCTRL2V/div

Time 100s/div

VFB100mV/div

Soft Start Waveform

VIN=3.6V, 5 LEDs, ILED=20mA Dimming Control

Two typical types of dimming control circuit are present as below. First, controlling CTRL Pin voltage to change operation state is a good choice.

Second, changing the feedback voltage to get appropriate duty and luminous intensity is also useful.

(1) Adding a Control Signal to CTRL Pin

Add a PWM Signal to CTRL pin directly. The AP3019A is turned on or off by the PWM signal when it is applied on the CTRL pin. The typical

frequency of this PWM signal can be up to 2kHz. Please refer to Figure Dimming Control Using a PWM Signal in CTRL Pin.

Dimming Control Using a PWM Signal in CTRL Pin

(2) Changing the Effective Feedback Voltage

There are three methods to change the effective feedback voltage.

First, adding a constant DC voltage through a resistor divider to FB pin can control the dimming. Changing the DC voltage or resistor between the

FB Pin and the DC voltage can get appropriate luminous intensity. Comparing with all kinds of PWM signal control, this method features a stable

output voltage and LEDs current. Please refer Figure Dimming Control Using DC Voltage.

Dimming Control Using DC Voltage

AP3019A

CTRL

up to 2kHz

R1

10

FB

AP3019A

R2

5K

R3

90K

VDC

Effective

Feedback Voltage





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Application Information (Cont.)

Second, using a filtered PWM signal can do it. The filtered PWM signal can be considered as a varying and adjustable DC voltage.

R1

10

FB

AP3019A

R2

5K

R3

90K

PWMR4

10KC

0.1F

Effective

Feedback Voltage

Dimming Control Using a Filtered PWM Voltage

Third, using a logic signal can change the feedback voltage. For example, the FB pin is connected to the GND through a MOSFET and a resistor.

And this MOSFET is controlled a logic signal. The luminous intensity of LEDs will be changed when the MOSFET turns on or off.

R1

FB

AP3019A

R2Logic

Signal 2N7002

Effective

Feedback Voltage

Dimming Control Using Logic Signal

Ordering Information

AP3019A X X - X

PackingPackageProduct Name

K: SOT-23-6

KT: TSOT-23-6

RoHS/Green

G1:RoHS Compliant

and GreenTR: Tape & Reel

Package Temperature Range Part Number Marking ID Packing Type

SOT-23-6 -40 to +85C AP3019AKTR-G1 GAS Tape & Reel

TSOT-23-6 -40 to +85C AP3019AKTTR-G1 L8E Tape & Reel





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Package Outline Dimensions (All dimensions in mm(inch).)

(1) Package Type: SOT-23-6

2.820(0.111)

3.100(0.122)

2.6

50

(0.1

04

)

3.0

00

(0.1

18

)

1.5

00

(0.0

59

)

1.7

00

(0.0

67

)

0.950(0.037)TYP

1.800(0.071)

2.000(0.079)

0.300(0.012)

0.500(0.020)

0.700(0.028)REF

0.100(0.004)

0.200(0.008)

0°

8°

0.200(0.008)

0.300(0.012)

0.600(0.024)

0.000(0.000)

0.150(0.006)

0.900(0.035)

1.300(0.051)

1.450(0.057)

MAX

1 2 3

456

Pin 1 Mark





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Package Outline Dimensions (All dimensions in mm(inch).) (Cont.)

(2) Package Type: TSOT-23-6

2.800(0.110)

3.000(0.118)

1.500(0.059)

1.700(0.067)

2.600(0.102)

3.000(0.118)

0.950(0.037)

BSC

1.900(0.075)

BSC

0.700(0.028)

0.900(0.035)

0.000(0.000)

0.100(0.004) 0.350(0.014)

0.510(0.020)

0

8

0.370(0.015)

MIN

0.100(0.004)

0.250(0.010)

0.250(0.010)

BSC

GAUGE

PLANE

R0.100(0.004)

MIN

Pin 1 Dot by

Marking

1.000(0.039)

MAX





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IMPORTANT NOTICE 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.

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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. Copyright © 2018, Diodes Incorporated www.diodes.com



Documents

SW 1 6 VIN AP3019A - Diodes Incorporated · WHITE LED STEP-UP CONVERTER 5 Description The AP3019A is an inductor-based DC/DC converter designed to drive ... Uses Tiny 1mm Tall Inductor