Page 1
Data Sheet
4-Channel Charge Pump LED Driver with Current Balancing and Wide Range PWM Dimming AP3605
General Description
The AP3605 is a step-up DC/DC converter based on
1.5x charge pump current source, it is specially
designed for LED supplies in backlight display.
The AP3605 can provide constant current up to 20mA
for each LED, which is programmed by an external
resistor, so it has a total capability to provide 80mA for
4 LEDs. The chip has a good performance of LED
current matching and allows PWM brightness dimming control. Additionally, high switching frequency
up to 1MHz enables the use of two small external
flying capacitors. Internal soft-start circuitry prevents
excessive inrush current during start-up.
The AP3605 supply voltage range is from 2.7V to
5.5V, ideally suited for applications powered by the Liion battery.
The AP3605 is available in a 3mmx3mm QFN-3x3-16
tiny package. Its operating temperature range is -40
o
C.
to 85
o
Features
· Regulated Output Current with ±3% Matching
· Regulated ±10% Output Current Source
· Drive up to 4 LEDs at 20mA Each
· Wide Operating Voltage Range: 2.7V to 5.5V
· High Efficiency up to 93%
· High Operating Frequency: 1MHz
· Built-in Soft-Start to Limit the Inrush Current
· LED Brightness Control through PWM and Ana-
log Signal
· PWM Dimming Frequency up to 50kHz
· Built-in Standby Mode to Get PWM Dimming
Duty Cycle Control Linearity
· Built-in OTSD (Over Temperature Shutdown)
Function to Protect the Device from Burn Out
Applications
· Mobile Phone
C
· MP3, MP4
· White LED Backlight in Mobile Phone, PDA
QFN-3x3-16
Figure 1. Package Type of AP3605
Jan. 2013 Rev. 1. 8 BCD Semiconductor Manufacturing Limited
1
Page 2
Data Sheet
E P
5678
1
2
3
49
12
Pin 1 Mark
11
10
13
141516
4-Channel Charge Pump LED Driver with Current Balancing and Wide Range PWM Dimming AP3605
Pin Configuration
FN Package
(
QFN-3x3-16
)
C1
D1D2
V
IN2
EN
ISET
AGND
C1+
-
C2+
V
OUT2
Exposed PAD, Connected to AGND
D4
V
OUT1
PGND
C2-
V
D3
IN1
Note: Pin 2 should be connected with Pin 8 and Pin 5 should be connected with Pin 13 on PCB board.
Figure 2. Pin Configuration of AP3605 (Top View)
Pin Description
Pin Number Pin Name Function
1, 16, 15, 14 D4 to D1 Current Source Output. Connect the anode of the white LEDs to these outputs
2, 8
3 PGND Power Ground. Connect this pin with power ground plane
4C2-
5, 13 V
6C1-
7C2+
9C1+
10 AGND
11 ISET
12 EN
V
OUT1, VOUT2
IN1, VIN2
Output Pin 1 and 2, must be connected together. The output capacitor should be placed
closely to these pins
Flying Capacitor 2 Negative Terminal. The flying capacitor 2 should be connected as close
to this pin as possible
Supply Voltage Input 1 and 2, must be connected together
Flying Capacitor 1 Negative Terminal. The flying capacitor 1 should be connected as close
to this pin as possible
Flying Capacitor 2 Positive Terminal. The flying capacitor 2 should be connected as close to
this pin as possible
Flying Capacitor 1 Positive Terminal. The flying capacitor 1 should be connected as close to
this pin as possible
Analog Ground. Connect this pin with control signal ground plane. PGND, AGND and the
exposed PAD should be connected together
Current Source Set Pin. Connect a resistor between this pin and GND to set the maximum
LED current
Enable Control Input. Logic high enables the IC; while logic low forces the device into shutdown mode to reduce the supply current to less than 1μA. Add a PWM signal to this pin to
achieve brightness control
Jan. 2013 Rev. 1. 8 BCD Semiconductor Manufacturing Limited
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Page 3
Data Sheet
5
15
11
1
Voltage
Reference
6
1.5x Charge Pump
4-Channel
Current
Source
47 9
16
14
3
12
10
13
8
2
LDO
Soft
Start
1MHz
OSC
Standby
OTSD
+
_
Error
AMP
4-Channel Charge Pump LED Driver with Current Balancing and Wide Range PWM Dimming AP3605
Functional Block Diagram
C2- C2+ C1+
C1-
V
OUT2
V
OUT1
D1
V
IN1
D2
D3
D4
ISET
V
IN2
EN
PGND
Figure 3. Functional Block Diagram of AP3605
AGND
Ordering Information
AP3605 -
Circuit Type
Package
FN: QFN-3x3-16
Package Temperature Range Part Number Marking ID Packing Type
QFN-3x3-16
Note 1: AP3605FNTR-E1 is a green product.
-40 to 85
o
C
AP3605FNTR-E1 (Note 1) F1A Tape & Reel
Jan. 2013 Rev. 1. 8 BCD Semiconductor Manufacturing Limited
E1: RoHS
TR: Tape and Reel
3
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Data Sheet
4-Channel Charge Pump LED Driver with Current Balancing and Wide Range PWM Dimming AP3605
Absolute Maximum Ratings (Note 2)
Parameter Symbol Value Unit
Input Voltage V
EN Pin Voltage V
V
Pin Voltage V
OUT1
V
Pin Voltage V
OUT2
ISET Pin Voltage V
Output Current at V
Pin I
OUT2
OUT2
Thermal Resistance (Junction to Ambient, no Heat sink) R
Operating Junction Temperature T
Storage Temperature Range T
Lead Temperature (Soldering, 10sec) T
LEAD
IN
EN
OUT1
OUT2
ISET
θJA
J
STG
-0.3 to 6 V
-0.3 to 6 V
-0.3 to 6 V
-0.3 to 6 V
-0.3 to 6 V
150 mA
60
150
-65 to 150
260
o
C/W
o
C
o
C
o
C
ESD (Human Body Model) 2000 V
Note 2: 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
Input Voltage
Operating Temperature T
Current Source Set Resistor R
V
ISET
IN
A
Jan. 2013 Rev. 1. 8 BCD Semiconductor Manufacturing Limited
4
2.7 5.5 V
-40 85
o
1.44 kΩ
C
Page 5
Data Sheet
4-Channel Charge Pump LED Driver with Current Balancing and Wide Range PWM Dimming AP3605
Electrical Characteristics
(VIN=3.5V, VEN=VIN, R
otherwise specified. )
=1.8kΩ, C
ISET
FLY1=CFLY2=CIN=COUT
=1μF, TA=25
Parameter Symbol Conditions Min Typ Max Unit
Input Section
o
C, VD1=VD2=VD3=VD4=3.4V, unless
Input Voltage V
Supply Current I
Shutdown Supply Current I
Charge Pump Section
Switching Frequency f
Efficiency
Current Source Section
Maximum Output Current per
Source
Current Matching between Any
Two Outputs
Output Current Line Regulation
I
D-MATCH
(ΔI
Current Matching between Any
Two Outputs under Different LED
ΔI
Forward Voltage
Reference Voltage for Current Set
ID to I
Current Ratio
SET
V
ID=0 to 40 mA 2.7 5.5 V
IN
No Load, ISET floating 1.5 2.5 mA
CC
SHDN
OSC
I
VEN=GND 0.1 1 μA
0.65 1 1.35 MHz
VIN=3.5V, ID=40mA Total 93 %
η
DX
3.2V≤VIN≤5.5V,
T
=-40oC to 85oC
A
18 20 22 mA
-3 3 %
)/
D/ID
ΔV
D/ID
ISET
3.5V≤V
3.0V≤VD≤4.0V, VIN=3.5V
≤5.5V
IN
-2 2 %/V
-5 5 %
1.193 1.23 1.267 V
K 100 120 140
Enable Section
EN High Level Threshold Voltage V
EN Low Level Threshold Voltage V
EN Input Leakage Current I
EN Low Threshold Time for
Standby State
t
IH
IL
EN
STB
VEN=5.5V -1 1 μA
1.4 V
0.5 V
2ms
Tot a l Dev i ce
Soft-Start Time t
Thermal Shutdown T
Thermal Shutdown Hysteresis T
OTSD
HYS
ID=80mA Total 400 μs
SS
160
20
o
C
o
C
Jan. 2013 Rev. 1. 8 BCD Semiconductor Manufacturing Limited
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Data Sheet
-50 -25 0 25 50 75 100 125 150
0.75
0.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
1.20
1.25
VIN=3.5V
Frequency (MHz)
Junction Temperature (OC)
-50 -25 0 25 50 75 100 125 150
0.9
1.0
1.1
1.2
1.3
1.4
1.5
1.6
Supply Current (mA)
Junction Temperature (OC)
VIN=3.5V, No Load, R
ISET
Open
2.53.03.54.04.55.05.5
0.90
0.95
1.00
1.05
1.10
1.15
1.20
1.25
1.30
Supply Current (mA)
Input Voltage (V)
R
ISET
Open
-50 -25 0 25 50 75 100 125 150
1.210
1.215
1.220
1.225
1.230
1.235
1.240
1.245
1.250
V
ISET
(V)
Junction Temperature (OC)
4-Channel Charge Pump LED Driver with Current Balancing and Wide Range PWM Dimming AP3605
Typical Performance Characteristics
(VIN=3.5V, VEN=VIN, R
otherwise specified. V
OUT
ISET
=1.8kΩ, C
FLY1=CFLY2=CIN=COUT
=1μF, TA=25
is the output voltage when VOUT1 and VOUT2 are connected.)
o
C, VD1=VD2=VD3=VD4=3.4V, unless
Figure 4. Supply Current vs. Junction Temperature Figure 5. Supply Current vs. Input Voltage
Figure 6. Frequency vs. Junction Temperature Figure 7. Reference Voltage vs. Junction Temperature
Jan. 2013 Rev. 1. 8 BCD Semiconductor Manufacturing Limited
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Data Sheet
2.5 3.0 3.5 4.0 4.5 5.0 5.5
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
1.05
1.10
V
IH
and V
IL
(V)
Input Voltage (V)
V
IH
V
IL
0 20 40 60 80 100 120
4.5
4.6
4.7
4.8
4.9
5.0
5.1
Output Voltage (V)
Output Current (mA)
2.5 3.0 3.5 4.0 4.5 5.0 5.5
20
30
40
50
60
70
80
ID=20mA ID=60mA
ID=40mA ID=80mA
I
DIODE
(mA)
Input Voltage (V)
3.0 3.2 3.4 3.6 3.8 4.0
20
30
40
50
60
70
80
ID=20mA ID=60mA
ID=40mA ID=80mA
I
DIODE
(mA)
V
DIODE
(V)
4-Channel Charge Pump LED Driver with Current Balancing and Wide Range PWM Dimming AP3605
Typical Performance Characteristics (Continued)
(VIN=3.5V, VEN=VIN, R
otherwise specified. V
OUT
ISET
=1.8kΩ, C
FLY1=CFLY2=CIN=COUT
=1μF, TA=25
is the output voltage when VOUT1 and VOUT2 are connected.)
o
C, VD1=VD2=VD3=VD4=3.4V, unless
Figure 8. VIH and VIL vs. Input Voltage Figure 9. Output Voltage vs. Output Current
Figure 10. I
Jan. 2013 Rev. 1. 8 BCD Semiconductor Manufacturing Limited
DIODE
vs. Input Voltage Figure 11. I
7
DIODE
vs. V
DIODE
Page 8
Data Sheet
0 20 40 60 80 100 120
50
55
60
65
70
75
80
85
90
95
100
Efficiency (%)
Output Current (mA)
2.5 3.0 3.5 4.0 4.5 5.0 5.5
50
55
60
65
70
75
80
85
90
95
100
Efficiency (%)
Input Voltage (V)
I
OUT
=20mA
I
OUT
=40mA
I
OUT
=60mA
I
OUT
=80mA
I
OUT
=100mA
I
OUT
=120mA
4-Channel Charge Pump LED Driver with Current Balancing and Wide Range PWM Dimming AP3605
Typical Performance Characteristics (Continued)
(VIN=3.5V, VEN=VIN, R
otherwise specified. V
OUT
ISET
=1.8kΩ, C
FLY1=CFLY2=CIN=COUT
=1μF, TA=25
is the output voltage when VOUT1 and VOUT2 are connected.)
o
C, VD1=VD2=VD3=VD4=3.4V, unless
Figure 12. Efficiency vs. Output Current
V
EN
V
OUT
V
D
I
IN
Figure 14. Turn on Characteristic Figure 15. Turn off Characteristic
Jan. 2013 Rev. 1. 8 BCD Semiconductor Manufacturing Limited
Figure 13. Efficiency vs. Input Voltage
V
EN
V
OUT
V
D
I
IN
8
Page 9
Data Sheet
4-Channel Charge Pump LED Driver with Current Balancing and Wide Range PWM Dimming AP3605
Typical Performance Characteristics (Continued)
(VIN=3.5V, VEN=VIN, R
otherwise specified. V
OUT
ISET
=1.8kΩ, C
FLY1=CFLY2=CIN=COUT
=1μF, TA=25
is the output voltage when VOUT1 and VOUT2 are connected.)
o
C, VD1=VD2=VD3=VD4=3.4V, unless
V
V
OUT
V
V
V
OUT
I
V
IN
D
D
IN
I
D
D
Figure 16. Output Ripple @ ID=40mA Figure 17. Output Ripple @ ID=80mA
Jan. 2013 Rev. 1. 8 BCD Semiconductor Manufacturing Limited
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Data Sheet
1μF
C
OUT
1μF
C1
C1+
EN
V
OUT1
V
IN
D1
D2
D3
GND
C
IN
1μF
AP3605
D
4
C1- C2-C2+
1μF
C2
I
SET
EN
R
ISET
PWM Dimming
1kHz to 50kHz
Li-ion
Battery
V
OUT2
4-Channel Charge Pump LED Driver with Current Balancing and Wide Range PWM Dimming AP3605
Operation
The AP3605 is a high efficiency 1.5x fractional
charge pump with 4 channels of integrated current
source for white LED backlight applications. The
AP3605 consists of a linear regulator followed by a
1.5x charge pump which operates at 1MHz, 4
channels current source, a reference and other control
circuits. The linear regulator regulates its output
voltage to supply charge pump, guarantees that the
charge pump always operates at 5V output with 1.5x
mode. This configuration minimizes the output
ripple.
The charge pump can generate 80mA of output
current, so each of the 4 WLED can be powered with
Typical Application
up to 20mA of current. The maximum LED current is
set by a resistor connected to the ISET pin which
programs a reference current, then the reference
current is mirrored to set the LED current.
Applying a PWM signal to the EN pin can be used to
achieve LED brightness dimming. Integrated 2ms
standby function helps to enhance the dimming control. Detailed descriptions please see the related
application note.
Figure 18. AP3605 Typical Application Circuit with 4 WLEDs
Jan. 2013 Rev. 1. 8 BCD Semiconductor Manufacturing Limited
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Data Sheet
1μF
C
OUT
1μ
F
C1
C1+
EN
V
IN
D1
D2
D3
GND
C
IN
1μF
AP3605
D
4
C1- C2-C2+
1μF
C2
I
SET
EN
R
ISET
PWM Dimming
1kHz to 50kHz
Li-ion
Battery
V
OUT1
V
OUT2
4-Channel Charge Pump LED Driver with Current Balancing and Wide Range PWM Dimming AP3605
Typical Application (Continued)
Figure 19. AP3605 Typical Application Circuit with 3 WLEDs
Jan. 2013 Rev. 1. 8 BCD Semiconductor Manufacturing Limited
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Page 12
Data Sheet
0
.
7
0
0
(
0
.
0
2
8
)
0
.
9
0
0
(
0
.
0
3
5
)
0
.
0
0
0
(
0
.
0
0
0
)
0
.
0
5
0
(
0
.
0
0
2
)
0
.
1
7
8
(
0
.
0
0
7
)
0
.
2
2
8
(
0
.
0
0
9
)
0
.
1
8
0
(
0
.
0
0
7
)
0
.
2
8
0
(
0
.
0
1
1
)
B
S
C
0
.
5
0
0
(
0
.
0
2
0
)
1
.
7
0
0
(
0
.
0
6
7
)
R
E
F
1
.
7
0
0
(
0
.
0
6
7
)
R
E
F
0
.
5
0
0
(
0
.
0
2
0
)
0
.
3
0
0
(
0
.
0
1
2
)
E
x
p
o
s
e
d
P
a
d
P
i
n
1
M
a
r
k
3
.
1
0
0
(
0
.
1
2
2
)
3
.
1
0
0
(
0
.
1
2
2
)
2
.
9
0
0
(
0
.
1
1
4
)
N
1
PIN # 1 IDENTIFICATION
See DETAIL A
Pin 1 Options
DETAIL A
1
2
1
5
1
6
1
1
2
2
1
6
1
6
1
5
1
5
4-Channel Charge Pump LED Driver with Current Balancing and Wide Range PWM Dimming AP3605
Mechanical Dimensions
QFN-3x3-16
2
.
0
4
(
0
9
)
0
1
.
1
Unit: mm(inch)
Jan. 2013 Rev. 1. 8 BCD Semiconductor Manufacturing Limited
12
Page 13
BCD Semiconductor Manufacturing Limited
IMPORTANT NOTICE
IMPORTANT NOTICE
BCD Semiconductor Manufacturing Limited reserves the right to make changes without further notice to any products or specifi-
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
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
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
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.
other rights nor the rights of others.
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