Data Sheet
WHITE LED STEP-UP CONVERTER AP3032
Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
1
General Description
The AP3032 is an inductor-based DC/DC boost
converter designed to drive up to 4 rows of LEDs
with 7 series for each in parallel for backlight.
A constant frequency 1MHz PWM control scheme is
employed in this IC, which means tiny external
components can be used. Specifically, 1mm tall
6.8μH inductor and 1µF aluminum output capacitor
for the typical application is sufficient.
The over output voltage protection is equipped in
AP3032, which protects the IC under open load
condition. The AP3032 includes UVLO, soft-start,
stand-by mode, current limiting and OTSD to protect
the circuit under over load condition
The AP3032 is available in SOT-23-6 package.
Features
• Efficiency Up to 81%（VIN=5V, IOUT=80mA）
• Drives up to 4 Rows of WLEDs with 7 Series
for Each in Parallel (VIN=5V)
• Fast 1 MHz Switching Frequency
• Wide Input Voltage Range: 2.7V to 9V
• Low Feedback Voltage: 200mV
• 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
Applications
• 7’ to 10’ LCD Panels
• Digital Photo Frame
• GPS Receiver
Figure 1. Package Type of AP3032
SOT-23-6
Data Sheet
WHITE LED STEP-UP CONVERTER AP3032
Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
2
Pin Configuration
K Package
(SOT-23-6)
1
2
34
5
Pin 1 Mark
6
SW
GND
FB
VIN
OV
CTRL
Figure 2. Pin Configuration of AP3032 (Top View)
Pin Description
Pin Number Pin Name Function
1 SW Switch pin. Connect external inductor and Schottky
2 GND Ground
3 FB Voltage feedback. Reference voltage is 200mV
4 CTRL
Enable and dimming control pin. Connect to a high input to enable
the IC or a low input to disable the IC. Connect to a PWM input to
achieve dimming control If logic low time is less than about 0.7
ms, AP3032 is hold on standby mode, at which it shut down the
power switch but shield the soft-start function, to achieve high
frequency dimming
5 OV
Over voltage protection input. Connect to the output directly. On
OVP condition, the output voltage will clamp
6 VIN Input supply pin. Must be locally bypassed
Data Sheet
WHITE LED STEP-UP CONVERTER AP3032
Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
3
Functional Block Diagram
Q1
A2
A1 CONTROL
LOGIC
1.2MHz
OSCILLATOR
RAMP
GENERATOR
VREF
3
6
4
2
5
DRIVER
1.25V
COMPARATOR
OVP
200mV
1
SOFT
START
FB SW
OV
GND
CTRL
VIN
STAND BY
OVER
TEMPERATURE
DETECTOR
Figure 3. Functional Block Diagram of AP3032
Ordering Information
AP3032 -
Circuit Type
TR: Tape & Reel
Package
K: SOT-23-6
Package Temperature
Range Part Number Marking ID Packing Type
SOT-23-6 -40 to 85°C AP3032KTR-G1 GJL Tape & Reel
BCD Semiconductor's Pb-free products, as designated with "G1" suffix in the part number, are RoHS compliant
and green.
G1: Green
Data Sheet
WHITE LED STEP-UP CONVERTER AP3032
Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
4
Absolute Maximum Ratings (Note 1)
Parameter Symbol Value Unit
Input Voltage VIN 20 V
SW Pin Voltage VSW 38 V
FB Pin Voltage VFB 20 V
OV Voltage VOV 35 V
CTRL Pin Voltage VCTRL 20 V
Thermal Resistance (Junction to
Ambient, No Heat Sink) θJA 265 °C/W
Operating Junction Temperature TJ 150
°C
Storage Temperature Range TSTG -65 to 150 °C
Lead Temperature (Soldering, 10sec) TLEAD 260 °C
ESD (Machine Model) 200 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.
Recommended Operating Conditions
Parameter Symbol Min Max Unit
Operating Temperature Range TOP -40 85
°C
Input Voltage VIN 2.7 9 V
CTRL Pin Voltage VCTRL 9 V
Data Sheet
WHITE LED STEP-UP CONVERTER AP3032
Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
5
Electrical Characteristics
VIN=VCTRL=5.0V, unless otherwise specified. Specification with standard typeface are for TA= 25°C, and those in
boldface type apply over the full operating temperature rang (TA=-40°C to 85°C).
Parameters Symbol Conditions Min Typ Max Unit
SUPPLY VOLTAGE (VIN PIN)
Input Voltage VIN 2.7 9 V
Quiescent Current IQ VFB=VIN,
Not Switching 3.0 4.0 5.0 mA
Shutdown Supply Current ISHDN V
CTRL=0V 50 μA
ENABLE (EN PIN)
CTRL Pin Voltage VCTRL 1.2 V
CTRL Pin Bias Current ICTRL 60 μA
OUTPUT VOLTAGE
OVP Voltage VOVP 27 V
VOLTAGE REFERENCE (FB PIN)
Feedback Voltage VFB 188 200 212 mV
Feedback Bias Current IFB 35 100 μA
SWITCHING REGULATOR
Switching Frequency f 0.75 1 1.3 MHz
Maximum Duty Cycle DMAX 90 93 %
Switch Current Limit ILIMIT D=60% 1.2 1.4 A
Switch VCE Saturation Voltage VCE_SAT I
SW=1A 300 mV
Switch Leakage Current VSW=9V 0.01 5 μA
THERMAL SHUTDOWN
Thermal Shutdown TOTSD 160 ºC
Thermal Shutdown Hysteresis THYS 20 ºC
SOFT START
Soft-start Time tSS 300 μs
Standby Time tSTANDBY 0.7 ms
Data Sheet
WHITE LED STEP-UP CONVERTER AP3032
Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
6
Typical Performance Characteristics
The WLED forward voltage (VF) is 3.2V at ILED=20mA, unless otherwise noted.
Figure 4. Efficiency vs. Input Voltage Figure 5. Switch Current Limit vs. Duty Cycle
Figure 6. Minimum Operating Voltage vs. Temperature Figure 7. Quiescent Current vs. Input Voltage
3456789
0
10
20
30
40
50
60
70
80
90
100
Efficiency (%)
Input Voltage (V)
TA=25OC
LED:7S4P,20mA Per Channel
0 102030405060708090
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
TA=25oC
Current Limit (A)
Duty Cycle (%)
-60 -40 -20 0 20 40 60 80 100 120 140
2.20
2.25
2.30
2.35
2.40
2.45
2.50
2.55
2.60
2.65
2.70
Minimum Operating Voltage (V)
Temperature (oC)
23456789
3.7
3.8
3.9
4.0
4.1
4.2
4.3
4.4
4.5
4.6
4.7
Quiescent Current (mA)
Input Voltage (V)
TA= -40oC
TA= 25oC
TA= 85oC
Data Sheet
WHITE LED STEP-UP CONVERTER AP3032
Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
7
Typical Performance Characteristics (Continued)
The WLED forward voltage (VF) is 3.2V at ILED=20mA, unless otherwise noted.
Figure 8. Shutdown Quiescent Current vs. Input Voltage Figure 9. CT RL Pin Voltage vs. Temperature
Figure 10. CTRL Pin Current vs. CTRL Pin Voltage Figure 11. Feedback Voltage vs. Temperature
23456789
40
45
50
55
60
65
70
75
80
85
Shutdown Quiescent Current (μA)
Input Voltage (V)
TA= -40oC
TA= 25oC
TA= 85oC
-60 -40 -20 0 20 40 60 80 100 120 140
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
CTRL Pin Voltage (V)
Temperature (oC)
23456789
20
40
60
80
100
120
140
160
180
200
220
CTRL Pin Current (μA)
CTRL Pin Voltage (V)
-60 -40 -20 0 20 40 60 80 100 120 140
188
190
192
194
196
198
200
202
204
206
208
210
212
Feedback Voltage (mV)
Tempera ture (oC)
IOUT= 20mA
Data Sheet
WHITE LED STEP-UP CONVERTER AP3032
Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
8
Typical Performance Characteristics (Continued)
The WLED forward voltage (VF) is 3.2V at ILED=20mA, unless otherwise noted.
Figure 12. Frequency vs. Temperature Figure 13. OVP Voltage vs. Temperature
Figure 14. Case Temperature vs. Input voltage
-60 -40 -20 0 20 40 60 80 100 120 140
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
Frequency (MHz)
Temperature (oC)
3456789
20
30
40
50
60
70
80
90
100
Case Temperature (oC)
Input Voltage (V)
TA=25oC
7S4P,20mA Per Channel
-60 -40 -20 0 20 40 60 80 100 120 140
20
22
24
26
28
30
OVP Voltage (V)
Temperature (oC)
Data Sheet
WHITE LED STEP-UP CONVERTER AP3032
Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
9
Application Information
1. Operation
The AP3032 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 21.
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 non-inversion input of the PWM comparator A2.
When this voltage exceeds the output voltage level of
the error amplifier A1, 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.
2. LED Current Control
Refer to Figure 21, the LED current is controlled by
the feedback resistor RISET. 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 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:
LED
ISET
200
ImV
R=
3. Over Voltage Protection
The AP3032 has an internal open-load protection
circuit. When the LEDs are disconnected from circuit
or fail open, the output voltage is clamped at 27V.
The AP3032 will switch at a low frequency, and
minimize current to avoid input voltage drop.
4. Soft Start
The AP3032 has an internal soft start circuit to limit
th
the inrush current during startup. If logic low time on
CTRL pin is more than about 0.7ms and then enable
the IC, the AP3032 will start smoothly to protect
system departments. The time of startup is controlled
by internal soft start capacitor. Details please refer to
Figure 15.
Figure 15. Soft Start Waveform
5. Standby and Dimming
To avoid audio noise and achieve high frequency
dimming, AP3032 setup a standby function. If logic
low time on CTRL pin is less than about 0.7ms and
then enable the IC, AP3032 will hold on standby
mode and start directly to achieve high frequency
dimming. Details please refer to Figure 16.
Figure 16. Standby Waveform
Data Sheet
WHITE LED STEP-UP CONVERTER AP3032
Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
10
Application Information (Continued)
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.
5.1 Adding a Control Signal to CTRL Pin
Adding a PWM signal to CTRL pin directly, the
AP3032 is turned on and off by this signal. When the
PWM frequency is lower than 2.5kHz (Typ), the IC
works in the soft-start mode to dimming the light. But
we intense suggest set the PWM signal frequency
higher than 25kHz to avoid audio noise. In this
situation, IC works in the standby mode and start
directly to achieve dimming the light. More details
please refer to Figure 17 and Figure 18.
AP3032
CTRL
up to 25kHz
Figure 17. Dimming Control
Using a PWM Signal on CTRL Pin
Figure 18. High Frequency
(25kHz) Dimming Waveform
5.2 Changing the E ffective 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.
Comparing with all kinds of PWM signal control, this
method features a stable output voltage and LEDs
current. Please refer to Figure 19.
Figure 19. 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 20.
Figure 20. Dimming Control
Using Filtered PWM Voltage
Data Sheet
WHITE LED STEP-UP CONVERTER AP3032
Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
11
Typical Application
Figure 21. Typical Application of AP3032 (7S4P)
Data Sheet
WHITE LED STEP-UP CONVERTER AP3032
Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
12
Mechanical Dimensions
SOT-23-6 Unit: mm(inch)
2.820(0.111)
3.020(0.119)
2.650(0.104)
2.950(0.116)
1.500(0.059)
1.700(0.067)
0.950(0.037)TYP
1.800(0.071)
2.000(0.079)
0.300(0.012)
0.400(0.016)
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
123
4
5
6
Pin 1 Mark
IMPORTANT NOTICE
BCD Semiconductor Manufacturing Limited reserves the right to make changes without further notice to any products or specifi-
cations herein. BCD Semiconductor Manufacturing Limited does not assume any responsibility fo r use of any its products for any
particular purpose, nor does BCD Semiconductor Man ufacturing Limited assume any liability arising out of the application or use
of any its products or circuits. BCD Semiconductor Manufacturing Limited does not convey any license under its patent rights or
other rights nor the rights of others.
- Wafer Fab
Shanghai SIM-BCD Semiconductor Manufacturing Limited
800, Yi Shan Road, Shanghai 200233, China
Tel: +86-21-6485 1491, Fax: +86-21-5450 0008
BCD Semiconductor Manufacturing Limited
MAIN SITE
REGIONAL SALES OFFICE
Shenzhen Office
Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd. Shenzhen Office
Advanced Analog Circuits (Shanghai) Corporation Shenzhen Office
Room E, 5F, Noble Center, No.1006, 3rd Fuzhong Road, Futian District, Shenzhen 518026, China
Tel: +86-755-8826 7951
Fax: +86-755-8826 7865
Taiwan Office
BCD Semiconductor (Taiwan) Company Limited
4F, 298-1, Rui Guang Road, Nei-Hu District, Taipei,
Taiwan
Tel: +886-2-2656 2808
Fax: +886-2-2656 2806
USA Office
BCD Semiconductor Corporation
30920 Huntwood Ave. Hayward,
CA 94544, U.S.A
Tel : +1-510-324-2988
Fax: +1-510-324-2788
- IC Design Group
Advanced Analog Circuits (Shanghai) Corporation
8F, Zone B, 900, Yi Shan Road, Shanghai 200233, China
Tel: +86-21-6495 9539, Fax: +86-21-6485 9673
BCD Semiconductor Manufacturing Limited
http://www.bcdsemi.com
BCD Semiconductor Manufacturing Limited
IMPORTANT NOTICE
BCD Semiconductor Manufacturing Limited reserves the right to make changes without further notice to any products or specifi-
cations herein. BCD Semiconductor Manufacturing Limited does not assume any responsibility for use of any its products for any
particular purpose, nor does BCD Semiconductor Manufacturing Limited assume any liability arising out of the application or use
of any its products or circuits. BCD Semiconductor Manufacturing Limited does not convey any license under its patent rights or
other rights nor the rights of others.
- Wafer Fab
Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd.
800 Yi Shan Road, Shanghai 200233, China
Tel: +86-21-6485 1491, Fax: +86-21-5450 0008
MAIN SITE
REGIONAL SALES OFFICE
Shenzhen Office
Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd., Shenzhen Office
Unit A Room 1203, Skyworth Bldg., Gaoxin Ave.1.S., Nanshan District, Shenzhen,
China
Tel: +86-755-8826 7951
Fax: +86-755-8826 7865
Taiwan Office
BCD Semiconductor (Taiwan) Company Limited
4F, 298-1, Rui Guang Road, Nei-Hu District, Taipei,
Taiwan
Tel: +886-2-2656 2808
Fax: +886-2-2656 2806
USA Office
BCD Semiconductor Corp.
30920 Huntwood Ave. Hayward,
CA 94544, USA
Tel : +1-510-324-2988
Fax: +1-510-324-2788
- Headquarters
BCD Semiconductor Manufacturing Limited
No. 1600, Zi Xing Road, Shanghai ZiZhu Science-based Industrial Park, 200241, China
Tel: +86-21-24162266, Fax: +86-21-24162277
