BCDSEMI AP3031

Data Sheet
WHITE LED STEP-UP CONVERTER
AP3031
General Description
Features
The AP3031 is an inductor-based DC/DC boost converter designed to drive LED arrays. 1.4A switching
current allows AP3031 to be used in different 7' to 10'
LCD panel backlights (3*13 LED arrays typically).
·
Up to 92% Efficiency
(VIN=9V, IOUT=260mA)
·
Up to 84% Efficiency
(VIN=5V, IOUT=260mA)
·
·
·
·
·
·
·
Fast 1MHz Switching Frequency
Wide Input Voltage Range: 2.7V to 16V
Low 200mV Feedback Voltage
Output Over Voltage Protection
Cycle by Cycle Current Limit: 1.4A
Built-in Soft-start
Built-in Standby Mode to Achieve High Frequency PWM Dimming
Built-in Thermal Shutdown Function
Under Voltage Lockout
A constant frequency 1MHz PWM control scheme is
employed in this IC, which means tiny external components can be used. Specifically, 1mm tall 4.7µH
inductor and 0.47µF output capacitor for the typical
application is sufficient.
The over output voltage protection is equipped in
AP3031, which protects the IC under open load condition. The AP3031 includes UVLO, soft-start, current
limit and OTSD to protect the circuit.
·
·
The AP3031 is available in standard SOT-23-6, TSOT23-6 and SOIC-8 packages.
Applications
·
·
·
·
·
SOT-23-6
7' to 10' LCD Panels
Digital Photo Frame
GPS Receiver
EPC
PDVD
TSOT-23-6
SOIC-8
Figure 1. Package Types of AP3031
Apr. 2009 Rev. 1. 3
BCD Semiconductor Manufacturing Limited
1
Data Sheet
WHITE LED STEP-UP CONVERTER
AP3031
Pin Configuration
K/KT Package
(SOT-23-6/TSOT-23-6)
M Package
(SOIC-8)
Pin 1 Dot by Marking
SW
1
6
VIN
GND
2
5
OV
FB
3
4
CTRL
FB
1
8
CTRL
GND
2
7
OV
GND
3
6
GND
SW
4
5
VIN
Figure 2. Pin Configuration of AP3031 (Top View)
Pin Description
Pin Number
6-Pin
8-Pin
Pin Name
1
4
SW
2
2, 3, 6
GND
3
1
FB
Function
Switch Pin. Connect external inductor and Schottky
Ground Pin
Voltage Feedback Pin. Reference voltage is 200mV
Enable and Dimming Control Pin. Connect to a high input to enable the IC or a low input to
disable the IC.
If logic low time is more than about 0.7ms and then enable the IC, the AP3031 will soft start to
protect system departments. If logic low time is less than about 0.7ms and then enable the IC,
the AP3031 will hold on standby mode and start directly to achieve high frequency dimming
4
8
CTRL
5
7
OV
Over-voltage Protection Input Pin. Connect to the output directly. On OVP condition, the output voltage will be clamped
6
5
VIN
Input Supply Pin. Must be locally bypassed
Apr. 2009 Rev. 1. 3
BCD Semiconductor Manufacturing Limited
2
Data Sheet
WHITE LED STEP-UP CONVERTER
AP3031
Functional Block Diagram
FB
SW
1 (4)
3 (1)
SOFT
START
5 (7)
OV
6 (5)
VIN
V REF
1 .25 V
DRIVER
A1
200 mV
A2
CONTROL
LOGIC
COMPARATOR
OVER
TEMPERATURE
DETECTOR
Q1
2
(2, 3, 6)
Σ
4 (8)
CTRL
STANDBY
To Control
Logic
OV
GND
RAMP
GENERATOR
1 MHz
OSCILLATOR
A (B)
A SOT-23-6/TSOT-23-6
B SOIC-8
Figure 3. Functional Block Diagram of AP3031
Ordering Information
AP3031
-
Circuit Type
G1: Green
Package
K: SOT-23-6
KT: TSOT-23-6
M: SOIC-8
Package
Temperature
Range
SOT-23-6
TSOT-23-6
SOIC-8
-40 to 85oC
TR: Tape and Reel
Blank: Tube
Part Number
Marking ID
Packing Type
AP3031KTR-G1
GEC
Tape & Reel
Tape & Reel
AP3031KTTR-G1
L1E
AP3031M-G1
3031M-G1
Tube
AP3031MTR-G1
3031M-G1
Tape & Reel
BCD Semiconductor's Pb-free products, as designated with "G1" suffix in the part number, are RoHS compliant and green.
Apr. 2009 Rev. 1. 3
BCD Semiconductor Manufacturing Limited
3
Data Sheet
WHITE LED STEP-UP CONVERTER
AP3031
Absolute Maximum Ratings (Note 1)
Parameter
Symbol
Value
Unit
Input Voltage
VIN
20
V
SW Voltage
VSW
38
V
FB Voltage
VFB
20
V
VCTRL
20
V
CTRL Voltage
Thermal Resistance
(Junction to Ambient, No Heat Sink)
θJA
Operating Junction Temperature
SOT-23-6/TSOT-23-6
265
SOIC-8
120
oC/W
TJ
150
oC
TSTG
-65 to 150
oC
TLEAD
260
o
ESD (Machine Model)
600
V
ESD (Human Body Model)
4000
V
Storage Temperature Range
Lead Temperature (Soldering, 10sec)
C
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.
Recommended Operating Conditions
Parameter
Symbol
Min
Max
Operating Temperature Range
TOP
-40
85
o
Input Voltage
VIN
2.7
16
V
CTRL Voltage
VCTRL
16
V
Apr. 2009 Rev. 1. 3
Unit
C
BCD Semiconductor Manufacturing Limited
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Data Sheet
WHITE LED STEP-UP CONVERTER
AP3031
Electrical Characteristics
(VIN=5.0V, VCTRL =5.0V, TA=25oC, unless otherwise specified.)
Parameter
Symbol
Operating Voltage
VIN
Feedback Voltage (Note 2)
VFB
FB Pin Bias Current
IFB
Quiescent Current
IQ
Shutdown Quiescent Current
ISHDN
Conditions
Min
Typ
Max
Unit
16
V
200
212
mV
35
100
nA
2.7
IOUT=20mA, 3 LEDs,
TA=-40oC to 85oC
188
VFB=VIN, no switching
3.0
4.0
5.0
mA
VCTRL=0V
20
50
80
µA
1.3
MHz
Switching Frequency
f
0.75
1
Maximum Duty Cycle
DMAX
90
93
%
Switch Current Limit (Note 3)
ILIMIT
1.2
1.4
A
Switch VCE Saturation Voltage
VCESAT
ISW=0.6A
300
mV
VSW=16V
0.01
Switch Leakage Current
CTRL Pin Voltage
VCTRL
D=60%
Active high
5
1.8
µA
V
Active low
0.5
35
60
85
µA
CTRL Pin Bias Current
ICTRL
OVP Voltage
VOVP
17
V
Soft-start Time
tSS
250
µs
Standby Time
tSTB
0.7
ms
Thermal Shutdown
TOTSD
155
oC
Thermal Resistance
(Junction to Case)
θJC
60
oC/W
Note 2: The bold type specifications of full temperature range are guaranteed by design (GBD).
Note 3: The switch current limit is related to duty cycle. Please refer to Figure 15 for detail.
Apr. 2009 Rev. 1. 3
BCD Semiconductor Manufacturing Limited
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Data Sheet
WHITE LED STEP-UP CONVERTER
AP3031
Typical Performance Characteristics
90
95
85
90
80
85
75
80
Efficiency (%)
Efficiency (%)
(WLED forward voltage (VF)=3.2V at IF=20mA, unless otherwise noted.)
70
65
60
75
70
65
o
o
55
VIN=5V, VOUT=10V, TA=25 C
60
50
CIN=10µF, COUT=0.47µF, L=4.7µH
55
45
0
VOUT=10V, IOUT=260mA,TA=25 C
CIN=10µF, COUT=0.47µF, L=4.7µH
50
3.5
20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340
4.0
4.5
5.0
5.5
6.5
7.0
7.5
8.0
8.5
9.0
Figure 4. Efficiency vs. Output Current
Figure 5. Efficiency vs. Input Voltage
4.7
2.65
4.6
2.60
4.5
Quiescent Current (mA)
2.70
2.55
2.50
2.45
2.40
2.35
4.4
4.3
4.2
4.1
4.0
o
TA= -40 C
2.30
3.9
TA= 25 C
2.25
3.8
TA= 85 C
2.20
-60
9.5
Input Voltage (V)
Output Current (mA)
Minimum Operating Voltage (V)
6.0
o
o
3.7
-40
-20
0
20
40
60
80
100
120
2
140
4
6
8
10
12
14
16
Input Voltage (V)
o
Temperature ( C)
Figure 6. Minimum Operating Voltage vs. Temperature
Figure 7. Quiescent Current vs. Input Voltage
Apr. 2009 Rev. 1. 3
BCD Semiconductor Manufacturing Limited
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Data Sheet
WHITE LED STEP-UP CONVERTER
AP3031
Typical Performance Characteristics (Continued)
85
2.0
80
1.8
75
CTRL Pin Voltage (V)
Shutdown Quiescent Current (µA)
(WLED forward voltage (VF)=3.2V at IF=20mA, unless otherwise noted.)
70
65
60
55
o
TA= -40 C
50
1.6
1.4
1.2
1.0
0.8
o
TA= 25 C
0.6
o
45
TA= 85 C
0.4
-60
40
2
4
6
8
10
12
14
16
-40
-20
0
20
40
60
80
100
120
140
o
Temperature ( C)
Input Voltage (V)
Figure 8. Shutdown Quiescent Current vs. Input Voltage
Figure 9. CTRL Pin Voltage vs. Temperature
212
220
210
200
208
Feedback Voltage (mV)
CTRL Pin Current (µA)
180
160
140
120
100
80
60
206
204
202
200
198
196
194
192
40
IOUT= 20mA
190
188
-60
20
2
4
6
8
10
12
14
16
18
-40
-20
0
20
40
60
80
100
120
140
o
Temperature ( C)
CTRL Pin Voltage (V)
Figure 10. CTRL Pin Current vs. CTRL Pin Voltage
Figure 11. Feedback Voltage vs. Temperature
Apr. 2009 Rev. 1. 3
BCD Semiconductor Manufacturing Limited
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Data Sheet
WHITE LED STEP-UP CONVERTER
AP3031
Typical Performance Characteristics (Continued)
(WLED forward voltage (VF)=3.2V at IF=20mA, unless otherwise noted.)
20
1.4
1.3
19
OVP Voltage (V)
Frequency (MHz)
1.2
1.1
1.0
0.9
18
17
16
0.8
15
0.7
0.6
-60
-40
-20
0
20
40
60
80
100
120
14
-60
140
-40
-20
0
20
40
60
80
100
120
140
o
Temperature ( C)
o
Temperature ( C)
Figure 13. OVP Voltage vs. Temperature
Figure 12. Frequency vs. Temperature
1.20
2.0
1.15
1.9
o
TA=-40 C
o
Switch Current Limit (A)
Frequency (MHz)
1.10
1.05
1.00
0.95
0.90
0.85
1.8
TA=25 C
1.7
TA=85 C
o
1.6
1.5
1.4
1.3
0.80
1.2
0.75
1.1
1.0
10
0.70
2
4
6
8
10
12
14
16
18
20
30
40
50
60
70
80
90
Duty Cycle (%)
Input Voltage (V)
Figure 15. Switch Current Limit vs. Duty Cycle
Figure 14. Frequency vs. Input Voltage
Apr. 2009 Rev. 1. 3
BCD Semiconductor Manufacturing Limited
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Data Sheet
WHITE LED STEP-UP CONVERTER
AP3031
Typical Performance Characteristics (Continued)
650
80
600
75
550
70
500
Case Temperature ( C)
450
o
Switch Saturation Voltage (mV)
(WLED forward voltage (VF)=3.2V at IF=20mA, unless otherwise noted.)
400
350
300
250
200
o
TA=-40 C
150
o
100
TA=25 C
50
TA=85 C
0
0.0
o
65
60
55
50
45
o
40
VIN=5V, VOUT=10V, TA=25 C
35
CIN=10µF, COUT=0.47µF, L=4.7µH
30
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
1.1
20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340
Output Current (mA)
Switch Current (A)
Figure 16. Switch Saturation Voltage
Figure 17. Case Temperature vs. Output Current
vs. Switch Current
Apr. 2009 Rev. 1. 3
BCD Semiconductor Manufacturing Limited
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Data Sheet
WHITE LED STEP-UP CONVERTER
AP3031
Application Information
Soft Start
The AP3031 has an internal soft start circuit to limit
the inrush current during startup. If logic low time on
CTRL pin is more than about 0.7ms and then enable
the IC, the AP3031 will start smoothly to protect the
supplier. The time of startup is controlled by internal
soft-start capacitor. Details please refer to Figure 18.
Operation
The AP3031 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 Figure 3 and
Figure 24.
At the start of each oscillator cycle, 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 noninversion input of the PWM comparator A2. When this
voltage exceeds the output voltage level of the error
amplifier A1, the switch is turned off.
>0.7ms
VCTRL
5V/div
VSW
5V/div
IL
500mA/div
VOUT
10V/div
Time 80µs/div
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.
LED Current Control
Refer to Figure 24, the LED current is controlled by the
feedback resistor RISET. LEDs' current accuracy is
determined by the feedback voltage and resistor RISET,
so the precise resistors are preferred. The resistance of
RISET is in inverse proportion to the LED current since
the feedback reference is fixed at 200mV. The relation
for RISET and LED current (ILED)can be expressed as
below:
R ISET
Figure 18. Soft-start Waveform
VIN=5V, 3×13 LEDs, ILED=260mA
Standby and Dimming
To avoid audio noise and achieve high frequency dimming, AP3031 is equipped with standby function. If
logic low time on CTRL pin is less than about 0.7ms
and then enable the IC, the AP3031 will hold on
standby mode and start directly to achieve high frequency dimming. Details please refer to Figure 19.
VCTRL
5V/div
<0.7ms
VSW
5V/div
IL
500mA/div
VOUT
10V/div
200mV
=
I LED
Time 80µs/div
Over Voltage Protection
The AP3031 has an internal open load protection
circuit. When the LEDs are disconnected from circuit
or fail open, the output voltage is clamped at about
17V. The AP3031 will switch at a low frequency, and
minimize current to avoid input voltage drop.
Apr. 2009 Rev. 1. 3
Figure 19. Standby Waveform
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,
BCD Semiconductor Manufacturing Limited
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Data Sheet
WHITE LED STEP-UP CONVERTER
AP3031
Comparing with all kinds of PWM signal control, this
method features a stable output voltage and LEDs
current. Please refer to Figure 22.
Application Information (Continued)
changing the feedback voltage to get appropriate duty
and luminous intensity is also useful.
(1) Adding a Control Signal to CTRL Pin
Adding a PWM signal to CTRL pin directly, the
AP3031 is turned on and off by this signal. When the
PWM frequency is lower than 1kHz(Typ.), the IC
works in the soft-start mode to dimming the light. On
contrary, when the PWM frequency is higher than
1kHz(Typ.), the IC works in the standby mode: the
converter ceaselessly switches off and directly starts to
achieve light dimming. This standby function allows
AP3031 to support high frequency dimming (up to
25kHz or higher) to avoid audio noise. More details
please refer to Figure 20 and Figure 21.
AP3031
AP3031
FB
VDC
R3
R1
R2
Effective
Feedback Voltage
Figure 22. Dimming Control
Using DC Voltage
Second, using a filtered PWM signal can do it. The
filtered PWM signal can be considered as a varying
and adjustable DC voltage, please refer to Figure 23.
CTRL
AP3031
Figure 20. Dimming Control
Using a PWM Signal in CTRL Pin
FB
PWM
R4
C
R3
Effective
Feedback Voltage
R2
R1
VCTRL
2.5V/div
Figure 23. Dimming Control
Using Filtered PWM Voltage
VSW
5V/div
IL
500mA/div
Time 20µs/div
Figure 21. High Frequency (25kHz)
Dimming Waveform
(2) Changing the Effective Feedback Voltage
There are two popular 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.
Apr. 2009 Rev. 1. 3
BCD Semiconductor Manufacturing Limited
11
Data Sheet
WHITE LED STEP-UP CONVERTER
AP3031
Typical Application
VIN
5V
CIN
10µF
L 4.7µH
VIN
D
VOUT
SW
COUT
0.47µF
OV
CTRL
AP3031
On/Off
GND
3*13
FB
R ISET
Figure 24. Typical Application of AP3031 (3×13 WLEDs)
Apr. 2009 Rev. 1. 3
BCD Semiconductor Manufacturing Limited
12
Data Sheet
WHITE LED STEP-UP CONVERTER
AP3031
Mechanical Dimensions
SOT-23-6
Unit: mm(inch)
0°
2.820(0.111)
8°
3.020(0.119)
0.300(0.012)
0.400(0.016)
5
0.300(0.012)
0.600(0.024)
4
1.500(0.059)
1.700(0.067)
2.650(0.104)
2.950(0.116)
6
0.200(0.008)
Pin 1 Dot by Marking
1
2
3
0.700(0.028)REF
0.950(0.037)TYP
0.000(0.000)
0.100(0.004)
1.800(0.071)
2.000(0.079)
0.100(0.004)
0.200(0.008)
1.050(0.041) 1.050(0.041)
1.150(0.045) 1.250(0.049)
Apr. 2009 Rev. 1. 3
BCD Semiconductor Manufacturing Limited
13
Data Sheet
WHITE LED STEP-UP CONVERTER
AP3031
Mechanical Dimensions (Continued)
TSOT-23-6
Unit: mm(inch)
2.800(0.110)
3.000(0.118)
1.500(0.059)
1.700(0.067)
R0.100(0.004)
MIN
0°
8°
2.600(0.102)
3.000(0.118)
Pin 1 Dot by
Marking
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)
0.350(0.014)
0.510(0.020)
Apr. 2009 Rev. 1. 3
BCD Semiconductor Manufacturing Limited
14
Data Sheet
WHITE LED STEP-UP CONVERTER
AP3031
Mechanical Dimensions (Continued)
SOIC-8
4.700(0.185)
5.100(0.201)
7°
Unit: mm(inch)
0.320(0.013)
1.350(0.053)
1.750(0.069)
8°
8°
7°
0.675(0.027)
0.725(0.029)
D
5.800(0.228)
1.270(0.050)
6.200(0.244)
TYP
D
20:1
0.800(0.031)
0.300(0.012)
R0.150(0.006)
0.100(0.004)
0.200(0.008)
0°
8°
1.000(0.039)
3.800(0.150)
4.000(0.157)
0.330(0.013)
0.190(0.007)
0.250(0.010)
1°
5°
0.510(0.020)
0.900(0.035)
R0.150(0.006)
0.450(0.017)
0.800(0.031)
Note: Eject hole, oriented hole and mold mark is optional.
Apr. 2009 Rev. 1. 3
BCD Semiconductor Manufacturing Limited
15
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