Diodes AP3032 User Manual

WHITE LED STEP-UP CONVERTER AP3032

Data Sheet

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, I

•

• Drives up to 4 Rows of WLEDs with 7 Series

for Each in Parallel (V

• 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

=5V)

IN

=80mA）

OUT

Applications

• 7’ to 10’ LCD Panels

• Digital Photo Frame

• GPS Receiver

Figure 1. Package Type of AP3032

Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited

SOT-23-6

1

Data Sheet

WHITE LED STEP-UP CONVERTER AP3032

Pin Configuration

K Package

(SOT-23-6)

Pin 1 Mark

6

SW

1

VIN

5

GND

FB

Figure 2. Pin Configuration of AP3032 (Top View)

2

34

OV

CTRL

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

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

4 CTRL

5 OV

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
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

Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited

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Data Sheet

WHITE LED STEP-UP CONVERTER AP3032

Functional Block Diagram

FB SW

VIN

CTRL

6

4

V

REF

1.25V

STAND BY

200mV

3

A1

SOFT

START

RAMP

GENERATOR

1.2MHz

OSCILLATOR

A2

COMPARATOR

OVP

CONTROL

LOGIC

OVER

TEMPERATURE

DETECTOR

DRIVER

1

5

OV

Q1

2

GND

Figure 3. Functional Block Diagram of AP3032

Ordering Information

AP3032 -

Circuit Type

TR: Tape & Reel
Package
K: SOT-23-6

Package

SOT-23-6

Temperature

Range

-40 to 85°C

Part Number Marking ID Packing Type

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

Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited

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Data Sheet

WHITE LED STEP-UP CONVERTER AP3032

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 V

Thermal Resistance (Junction to
Ambient, No Heat Sink)

Operating Junction Temperature TJ 150

Storage Temperature Range T

Lead Temperature (Soldering, 10sec) T

ESD (Machine Model) 200 V

ESD (Human Body Model) 2000 V

20 V

CTRL

θ

JA

-65 to 150

STG

260

LEAD

265

°C/W

°C

°C

°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 Unit

Operating Temperature Range TOP -40 85

Input Voltage VIN 2.7 9 V

CTRL Pin Voltage V

9 V

CTRL

°C

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Data Sheet

WHITE LED STEP-UP CONVERTER AP3032

Electrical Characteristics

VIN=V
boldface type apply over the full operating temperature rang (T

Parameters Symbol Conditions Min Typ Max Unit

SUPPLY VOLTAGE (VIN PIN)

Input Voltage VIN 2.7 9 V

=5.0V, unless otherwise specified. Specification with standard typeface are for TA= 25°C, and those in

CTRL

=-40°C to 85°C).

A

Quiescent Current IQ

Shutdown Supply Current I

SHDN

V

FB=VIN,

Not Switching

V

CTRL

3.0 4.0 5.0 mA

=0V 50 μA

ENABLE (EN PIN)

CTRL Pin Voltage V

CTRL Pin Bias Current I

1.2 V

CTRL

60 μA

CTRL

OUTPUT VOLTAGE

OVP Voltage V

27 V

OVP

VOLTAGE REFERENCE (FB PIN)

Feedback Voltage V

188 200 212 mV

FB

Feedback Bias Current IFB 35 100 μA

SWITCHING REGULATOR

Switching Frequency f 0.75 1 1.3 MHz

Maximum Duty Cycle D

Switch Current Limit I

90 93 %

MAX

D=60% 1.2 1.4 A

LIMIT

Switch VCE Saturation Voltage V

ISW=1A 300 mV

CE_SAT

Switch Leakage Current VSW=9V 0.01 5 μA

THERMAL SHUTDOWN

Thermal Shutdown T

Thermal Shutdown Hysteresis T

160 ºC

OTSD

20 ºC

HYS

SOFT START

Soft-start Time tSS 300 μs

Standby Time t

Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited

STANDBY

0.7 ms

5

Data Sheet

WHITE LED STEP-UP CONVERTER AP3032

Typical Performance Characteristics

The WLED forward voltage (VF) is 3.2V at I

=20mA, unless otherwise noted.

LED

100

90
80
70
60

50
40

Efficiency (%)

30
20
10

0

3456789

Figure 4. Efficiency vs. Input Voltage Figur e 5. Switch Current Limit vs. Duty Cycle

2.70

2.65

2.60

2.55

2.50

2.45

2.40

2.35

Minimum Operating Voltage (V)

2.30

2.25

2.20

-60 -40 -20 0 20 40 60 80 100 120 140

Figure 6. Minimum Operating Voltage vs. Temperature Figure 7. Quiescent Current vs. Input Voltage

TA=25OC
LED:7S4P,20mA Per Channel

Input Voltage (V)

Temperature (oC)

1.8

1.7

1.6

1.5

1.4

1.3

Current Limit (A)

1.2

1.1

1.0
0 102030405060708090

4.7

4.6

4.5

4.4

4.3

4.2

4.1

Quiescent Current (mA)

4.0

3.9

3.8

3.7
23456789

TA=25oC

Duty Cycle (%)

TA= -40oC
TA= 25oC
TA= 85oC

Input Voltage (V)

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Data Sheet

WHITE LED STEP-UP CONVERTER AP3032

Typical Performance Characteristics (Continued)

The WLED forward voltage (V

) is 3.2V at I

F

=20mA, unless otherwise noted.

LED

85

80

75

70

65

60

55

50

Shutdown Quiescent Current (μA)

45

40

23456789

Input Voltage (V)

TA= -40oC
TA= 25oC
TA= 85oC

2.0

1.8

1.6

1.4

1.2

1.0

CTRL Pin Voltage (V)

0.8

0.6

0.4

-60 -40 -20 0 20 40 60 80 100 120 140

Figure 8. Shutdown Quiescent Current vs. Input Voltage Figure 9. CTRL Pin Voltage vs. Temperature

Temperature (oC)

220

200
180

160
140

120
100

CTRL Pin Current (μA)

80
60

40
20

23456789

CTRL Pin Voltage (V)

212
210
208
206
204
202
200
198
196

Feedback Voltage (mV)

194
192
190
188

-60 -40 -20 0 20 40 60 80 100 120 140

Temperature (oC)

I

OUT

Figure 10. CTRL Pin Current vs. CTRL Pin Voltage Figure 11. Feedback Voltage vs. Temperature

= 20mA

Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited

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Data Sheet

WHITE LED STEP-UP CONVERTER AP3032

Typical Performance Characteristics (Continued)

The WLED forward voltage (V

) is 3.2V at I

F

=20mA, unless otherwise noted.

LED

1.4

1.3

1.2

1.1

1.0

0.9

Frequency (MHz)

0.8

0.7

0.6

-60 -40 -20 0 20 40 60 80 100 120 140

Temperature (oC)

30

28

26

24

OVP Voltage (V)

22

20

-60 -40 -20 0 20 40 60 80 100 120 140

Temperature (oC)

Figure 12. Frequency vs. Temperature Figure 13. OVP Voltage vs. Temperature

100

90

80

C)

o

70

60

50

40

Case Temperature (

30

20

3456789

TA=25oC
7S4P,20mA Per Channel

Input Voltage (V)

Figure 14. Case Temperature vs. Input voltage

Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited

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Data Sheet

WHITE LED STEP-UP CONVERTER AP3032

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 R
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 R
proportion to the LED current since the feedback
reference is fixed at 200mV. The relation for R
and LED current (I

LED

. LEDs' current accuracy is

ISET

is in inverse

ISET

) can be expressed as below:

ISET

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.

200

I

mV

LED

R =

ISET

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

Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited

Figure 16. Standby Waveform

9

Data Sheet

WHITE LED STEP-UP CONVERTER AP3032

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.

5.2 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.
Comparing with all kinds of PWM signal control, this
method features a stable output voltage and LEDs
current. Please refer to Figure 19.

AP3032

CTRL

up to 25kHz

Figure 17. Dimming Control

Using a PWM Signal on CTRL Pin

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 18. High Frequency

(25kHz) Dimming Waveform

Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited

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Figure 2 0. Dimming Control

Using Filtered PWM Voltage

Data Sheet

WHITE LED STEP-UP CONVERTER AP3032

Typical Application

Figure 21. Typical Application of AP3032 (7S4P)

Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited

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Data Sheet

WHITE LED STEP-UP CONVERTER AP3032

Mechanical Dimensions

SOT-23-6 Unit: mm(inch)

0°
8°

0.200(0.008)

2.650(0.104)

2.950(0.116)

2.820(0.111)

3.020(0.119)

0.300(0.012)

0.400(0.016)

6

Pin 1 Mark

123

5

4

0.300(0.012)

0.600(0.024)

1.500(0.059)

1.700(0.067)

0.700(0.028)REF

0.950(0.037)TYP

1.800(0.071)

2.000(0.079)

0.000(0.000)

0.150(0.006)

0.900(0.035)

1.300(0.051)

1.450(0.057)
MAX

0.100(0.004)

0.200(0.008)

Dec. 2012 Rev. 1. 2 BCD Semiconductor Manufacturing Limited

12

BCD Semiconductor Manufacturing Limited

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