AP3019A
WHITE LED STEP-UP CONVERTER
Description
Pin Assignments
NEW PRODUCT
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.
(Top View)
Pin 1 Mark
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.
SW
1
6
VIN
GND
2
5
VOUT
FB
3
4
CTRL
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
AP3019A
Document number: DS41298 Rev. 3 - 2
K/KT Package
(SOT-23-6/TSOT-23-6)
Applications
Cellular Phones
Digital Cameras
LCD Modules
GPS Receivers
PDAs, Handheld Computers
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AP3019A
Typical Applications Circuit
NEW PRODUCT
V IN 3V
22 H
L
1
6
Control
Signal
VIN
5
SW
VOUT
C OUT
AP3019A
4
CIN
1F
CTRL
GND
FB
0.22F
3
10
2
C: X5R or X7R dielectric
L: SUMIDA CDRH5D28R-220NC or equivalent
This circuit can work in full temperature
Pin Descriptions
Pin Number
Pin Name
1
SW
Switch pin. Connect external inductor
2
GND
Ground
3
FB
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
AP3019A
Document number: DS41298 Rev. 3 - 2
Function
Voltage feedback pin. Reference voltage is 200mV
Input supply pin. Must be connected to a local bypass capacitor
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AP3019A
Functional Block Diagram
FB
SW
3
1
5
NEW PRODUCT
SOFT
START
VIN
6
VREF
1.25 V
OVP
DRIVER
A1
200mV
A2
Q
R
VOUT
Q1
S
COMPARATOR
2
CTRL
GND
4
RAMP
GENERATOR
1.2 MHz
OSCILLATOR
Absolute Maximum Ratings (Note 1)
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
-65 to +150
C
TSTG
Storage Temperature Range
TLEAD
Lead Temperature (Soldering, 10sec)
+260
C
–
ESD (Machine Model)
250
V
–
ESD (Human Body Model)
2000
V
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.
AP3019A
Document number: DS41298 Rev. 3 - 2
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AP3019A
Recommended Operating Conditions
Symbol
Min
Max
Unit
TOP
Operating Temperature Range
-40
+85
C
VIN
Input Voltage
2.5
16
V
–
16
V
VCTRL
NEW PRODUCT
Parameter
CTRL Pin Voltage
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
–
–
VIN (MAX)
Maximum Operating Voltage
–
–
–
16
VFB
Feedback Voltage (Note 2)
IOUT=20mA, 4 LEDs, TA=-40oC to +85oC
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
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
–
%
D=40%
–
550
–
ILIMIT
Switch Current Limit (Note 3)
D=80%
–
550
–
Switch VCE Saturation Voltage
ISW=250mA
–
360
–
mV
Switch Leakage Current
VSW=5V
–
0.01
5
A
High
1.8
–
–
Low
–
–
0.5
ISHDN
VCESAT
–
VCTRL
CTRL Pin Voltage
V
mA
V
ICTRL
CTRL Pin Bias Current
–
–
100
–
A
VOV
OVP Voltage
–
–
30
–
V
Schottky Forward Drop
ID=150mA
–
0.7
–
V
VR(Reverse Voltage)=23V
–
0.1
4
VR(Reverse Voltage)=27V
–
–
150
Soft Start Time
–
–
300
–
Thermal Resistance
(Junction to Case)
SOT-23-6
–
60
–
TSOT-23-6
–
60
–
VDROP
–
t
JC
Notes:
Schottky Leakage Current
A
s
C/W
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.
AP3019A
Document number: DS41298 Rev. 3 - 2
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AP3019A
Performance Characteristics (WLED forward voltage (VF) is 3.45V at IF=20mA, unless otherwise noted.)
Efficiency vs. Junction Temperature
Efficiency vs. Input Voltage
83
86
82
84
81
82
Efficiency (%)
Efficiency (%)
79
78
77
80
78
76
76
O
74
75
VIN=3.6V, IOUT=20mA, 8 LEDs
74
CIN=1F, COUT=0.22F, L=22H
73
-50
-25
0
25
50
IOUT=20mA, 8 LEDs,TA=+25 C
CIN=1F, COUT=0.22F, L=22H
72
75
70
3.0
100
3.5
4.0
o
Junction Temperature ( C)
4.5
5.0
Input Voltage (V)
Efficiency vs. LED’s Number
Schottky Forward Current vs. Schottky Forward Drop
86
350
85
Schottky Forward Current (mA)
300
84
Efficiency (%)
83
82
81
80
79
O
VIN=3.6V, IOUT=20mA,TA=+25 C
CIN=1F, COUT=0.22F, L=22H
78
77
2
3
4
5
6
7
250
200
150
100
50
76
0
8
0
200
400
600
800
1000
LED's Number
Schottky Forward Drop (mV)
Shutdown Quiescent Current vs. Input Voltage
Quiescent Current vs. Input Voltage
30
3.5
25
3.0
Quiescent Current (mA)
Shutdown Quiescent Current (A)
NEW PRODUCT
80
20
15
10
2.5
2.0
1.5
O
1.0
TA=-50 C
0.5
TA=+100 C
O
TA=+25 C
O
TA=+25 C
5
O
0
2
4
6
8
10
12
14
16
0.0
AP3019A
Document number: DS41298 Rev. 3 - 2
0
2
4
6
8
10
12
14
16
Input Voltage (V)
Input Voltage (V)
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AP3019A
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
1.40
6.0
1.35
5.5
1.30
Frequency (MHz)
Input Current (mA)
1.25
4.5
4.0
3.5
3.0
1.20
1.15
1.10
1.05
1.00
2.5
0.95
2.0
2.5
3.0
3.5
4.0
4.5
0.90
-50
5.0
-25
Input Voltage (V)
50
75
0.80
208
0.78
206
0.76
204
202
200
198
196
194
0.74
0.72
0.70
0.68
0.66
0.64
192
ID=150mA
0.62
-25
0
25
50
75
0.60
-50
100
-25
0
25
o
Junction Temperature ( C)
50
75
100
o
Junction Temperature ( C)
Schottky Leakage Current vs. Junction Temperature
Current Limit vs. Duty Cycle
700
0.50
VR=10V
0.40
VR=16V
0.35
VR=23V
600
Current Limit (mA)
0.45
0.30
0.25
0.20
500
400
300
0.15
O
0.10
-50 C
O
+25 C
O
+100 C
200
0.05
0.00
-50
100
Schottky Forward Drop vs. Junction Temperature
Schottky Forward Drop (V)
Feedback Voltage (mV)
25
o
210
190
-50
0
Junction Temperature ( C)
Feedback Voltage vs. Junction Temperature
Schottky Leakage Current (A)
NEW PRODUCT
5.0
-25
0
25
50
75
100
Junction Temperature ( C)
Document number: DS41298 Rev. 3 - 2
40
50
60
70
80
Duty Cycle (%)
o
AP3019A
100
30
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90
AP3019A
Performance Characteristics (WLED forward voltage (VF) is 3.45V at IF=20mA, unless otherwise noted.) (Cont.)
450
Saturation Voltage vs. Switch Current
1.8
CTRL Pin Voltage vs. Junction Temperature
1.7
Falling Edge
Rising Edge
1.6
350
CTRL Pin Voltage (V)
NEW PRODUCT
Saturation Voltage (mV)
400
300
250
200
150
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
100
0.6
50
50
100
150
200
250
0.5
-50
300
-25
Switch Current (mA)
0
25
50
75
100
O
Junction Temperature ( C)
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.
V IN 3V
L1
1
6
Control
Signal
4
C1
VIN
5
SW
VOUT
C2
AP3019A
CTRL
GND
FB
2
3
R1
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:
R1 =
200mV
I LED
AP3019A
Document number: DS41298 Rev. 3 - 2
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AP3019A
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
NEW PRODUCT
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.
II N
100mA/div
VO U T
5V/div
VF B
100mV/div
VC T RL
2V/div
Time 100s/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.
AP3019A
CTRL
up to 2kHz
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.
AP3019A
FB
VDC
R3
90K
R2
5K
R1
10
Effective
Feedback Voltage
Dimming Control Using DC Voltage
AP3019A
Document number: DS41298 Rev. 3 - 2
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AP3019A
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.
AP3019A
FB
NEW PRODUCT
PWM
R4
10K
Effective
Feedback Voltage
R1
10
R2
5K
R3
C
90K
0.1F
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.
AP3019A
FB
Effective
Feedback Voltage
R2
Logic
Signal
R1
2N7002
Dimming Control Using Logic Signal
Ordering Information
AP3019A X X - X
Product Name
Package
Packing
K: SOT-23-6
KT: TSOT-23-6
TR: Tape & Reel
G1:RoHS Compliant
and Green
Package
Temperature Range
SOT-23-6
-40 to +85C
AP3019AKTR-G1
GAS
Tape & Reel
TSOT-23-6
-40 to +85C
AP3019AKTTR-G1
L8E
Tape & Reel
AP3019A
Document number: DS41298 Rev. 3 - 2
Part Number
RoHS/Green
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Marking ID
Packing Type
August 2018
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AP3019A
Package Outline Dimensions (All dimensions in mm(inch).)
(1)
Package Type: SOT-23-6
0°
2.820(0.111)
8°
0.300(0.012)
0.500(0.020)
0.200(0.008)
5
4
2
3
0.300(0.012)
0.600(0.024)
1.500(0.059)
1.700(0.067)
6
2.650(0.104)
3.000(0.118)
NEW PRODUCT
3.100(0.122)
Pin 1 Mark
1
0.700(0.028)REF
0.950(0.037)TYP
0.000(0.000)
0.150(0.006)
1.800(0.071)
2.000(0.079)
0.100(0.004)
0.200(0.008)
0.900(0.035) 1.450(0.057)
MAX
1.300(0.051)
AP3019A
Document number: DS41298 Rev. 3 - 2
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AP3019A
Package Outline Dimensions (All dimensions in mm(inch).) (Cont.)
(2)
Package Type: TSOT-23-6
NEW PRODUCT
2.800(0.110)
3.000(0.118)
1.500(0.059)
1.700(0.067)
Pin 1 Dot by
Marking
R0.100(0.004)
MIN
0
8
2.600(0.102)
3.000(0.118)
0.370(0.015)
MIN
0.950(0.037)
BSC
0.100(0.004)
0.250(0.010)
1.900(0.075)
BSC
0.250(0.010)
BSC
GAUGE
PLANE
0.700(0.028)
0.900(0.035)
1.000(0.039)
MAX
0.000(0.000)
0.100(0.004)
AP3019A
Document number: DS41298 Rev. 3 - 2
0.350(0.014)
0.510(0.020)
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AP3019A
IMPORTANT NOTICE
NEW PRODUCT
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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).
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final and determinative format released by Diodes Incorporated.
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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
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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
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AP3019A
Document number: DS41298 Rev. 3 - 2
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