AME5142/5142A/5142B/DC-DC Boost Converter

AME
AME5142/5142A/5142B
n General Description
The AME5142/5142A/5142B is a Boost DC/DC converter specifically designed to drive white LEDs with a
constant current. The device can drive 1 to 6 LEDs in
series or multiple strings from a Li-lon cell. Series connection of the LEDs provides identical LED currents resulting in uniform brightness and eliminating the need for
ballast resistors. The AME5142/5142A/5142B switches
at 1.2MHz, allowing the use of tiny external components.
The input and output capacitor can be as small as 1µF(or
4.7µF), saving space and cost versus alternative solutions. A low feedback voltage minimizes power loss in
the current setting resistor for better efficiency. The
AME5142/5142A/5142B is available in SOT-26/TSOT-26
& SOT-25/TSOT-25 packages.
The only difference between AME5142, AME5142A and
AME5142B is feedback trip point. The AME5142 is 0.15V
and AME5142A/5142B is 0.104V.
n Features
l 1.2MHz Fixed Switching Frequency
High Efficiency 6 White LED Driver
With Open LED Protection
n Typical Application
L1
10µH
VIN 2.7V to 5.5V
CIN
4.7µF
VOUT
IN
COUT
1µF
SW
AME5142
AME5142A
EN AME5142BOVP
GND
FB
R1
7.5Ω
Figure 1: Circuit For Driving 2 White LEDs
L1
10µH
VIN 2.7V to 5.5V
CIN
4.7µF
VOUT
IN
COUT
1µF
SW
AME5142
AME5142A
EN AME5142BOVP
l 28V Over Voltage Protection
l Over Temperature Protection
l Under Voltage Lockout Protection
GND
l Internal Soft Start
FB
R1
7.5Ω
l 30V Internal Switch
l Drives Up to 6 LEDs from a 2.7V Supply at
20mA
l Only small external Capacitors and Inductor
Figure 2: Circuit For Driving 4 White LEDs
required
l Cycle-by-Cycle Current Limiting
l Up to 88% Efficiency
l Meet RoHS Standards
n Applications
l LCD Bias
l Hand-held Computers
l Battery Backup
l Digital Cameras
l Personal Navigation Device
L1
10µH
VIN 2.7V to 5.5V
CIN
4.7µF
VOUT
IN
COUT
1µF
SW
AME5142
AME5142A
EN AME5142BOVP
GND
FB
R1
7.5Ω
l Digital Picture Frame
l Smart Phone
Rev. C.02
Figure 3: Circuit For Driving 6 White LEDs
1
AME
AME5142/5142A/5142B
High Efficiency 6 White LED Driver
With Open LED Protection
„ Function Block Diagram
EN
SW
OVP
SHUTDOWN
CIRCUITRY
IN
Vref
Vref
1.25V
UVLO
OTP
R
+
R
0.15V
*
RAMP
GENERATOR
+
R
GM
Q
S
-
FB
DRIVER
Rc
Oscillator
MS
CURRENT
LIMIT COMP
+
Soft
Start
MS1
Cc
GND
* AME5142
feedback trip point is 0.15V. AME5142A and AME5142B feedback trip point is 0.104V.
Figure 4 : AME5142/5142A/5142B Block Diagram
2
Rev. C.02
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
n Pin Configuration
SOT-25/TSOT-25
Top View
5
4
SOT-26/TSOT-26 (Recommend)
Top View
AME5142AEEV
6
5
4
AME5142AAEEV
AME5142
AME5142A
AME5142AAEEY
AME5142BAEEY
AME5142
AME5142A
AME5142B
1. SW
2. GND
1. SW
2. GND
3. FB
1
2
3
4. EN
AME5142AEEY
3. FB
1
2
3
5. IN
4. EN
5. OVP
6. IN
(Recommend)
Die Attach:
Die Attach:
Conductive Epoxy
Conductive Epoxy
n Pin Description
AME5142AEEV/AME5142AAEEV
Pin Number
Pin Name
Pin Description
1
SW
Power Switch input.
This is the drain of the internal NMOS power switch. Minimize the metal
trace area connected to this pin to minimize EMI.
2
GND
Ground.
Tie directly to ground plane.
3
FB
Output voltage feedback input.
Connect the ground of the feedback network to an AGND (Analog Ground)
plane which should be tied directly to the GND pin.
4
EN
Enable control input, active high.
The enable pin is an active high control. Tie this pin above 1.5V to enable
the device. Tie this pin below 0.4V to turn off the device.
5
IN
Analog and Power input.
Input Supply Pin. Bypass this pin with a capacitor as close to the device
as possible.
Rev. C.02
3
AME
AME5142/5142A/5142B
High Efficiency 6 White LED Driver
With Open LED Protection
n Pin Description
AME5142AEEY/AME5142AAEEY/AME5142BAEEY (Recommend)
4
Pin Number
Pin Name
Pin Description
1
SW
Power Switch input.
This is the drain of the internal NMOS power switch. Minimize the metal
trace area connected to this pin to minimize EMI.
2
GND
Ground.
Tie directly to ground plane.
3
FB
Output voltage feedback input.
Connect the ground of the feedback network to an AGND(Analog Ground)
plane which should be tied directly to the GND pin.
4
EN
Enable control input, active high.
The enable pin is an active high control. Tie this pin above 1.5V to enable
the device. Tie this pin below 0.4V to turn off the device.
5
OVP
6
IN
Over Voltage Protection.
Analog and Power input.
Input Supply Pin. Bypass this pin with a capacitor as close to the device
as possible.
Rev. C.02
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
n Ordering Information
AME5142 x x x x xxx x
Special Feature
Output Voltage
Number of Pins
Package Type
Operating Ambient Temperature Range
Pin Configuration
Pin
Configuration
A
(SOT-25)
(TSOT-25)
A
(SOT-26)
(TSOT-26)
Rev. C.02
1. SW
2. GND
3. FB
4. EN
5. IN
Operating Ambient
Temperature
Range
Package
Type
E: -40OC to +85OC
E: SOT-2X
Number
of
Pins
V: 5
Y: 6
Output Voltage
Special Feature
ADJ: Adjustable
Y: Lead free & Low
profile
Z: Lead free
1. SW
2. GND
3. FB
4. EN
5. OVP
6. IN
5
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
n Ordering Information
AME5142A x x x x xxx x
Special Feature
Output Voltage
Number of Pins
Package Type
Operating Ambient Temperature Range
Pin Configuration
Note 1.
Note 1. AME5142 feedback trip point is 0.15V. AME5142A feedback trip point is 0.104V.
Pin
Configuration
A
(SOT-25)
(TSOT-25)
A
(SOT-26)
(TSOT-26)
6
1. SW
2. GND
3. FB
4. EN
5. IN
Operating Ambient
Temperature
Range
Package
Type
E: -40OC to +85OC
E: SOT-2X
Number
of
Pins
V: 5
Y: 6
Output Voltage
Special Feature
ADJ: Adjustable
Y: Lead free & Low
profile
Z: Lead free
1. SW
2. GND
3. FB
4. EN
5. OVP
6. IN
Rev. C.02
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
n Ordering Information
AME5142B x x x x xxx x
Special Feature
Output Voltage
Number of Pins
Package Type
Operating Ambient Temperature Range
Pin Configuration
Note 2.
Note 2. AME5142 feedback trip point is 0.15V. AME5142A and AME5142B feedback trip point is 0.104V.
The only difference between AME5142A and AME5142B is the behavior of OVP.
Please refer to Output Over-Voltage Protection.
Pin
Configuration
A
(SOT-26)
Rev. C.02
1. SW
2. GND
3. FB
4. EN
5. OVP
6. IN
Operating Ambient
Temperature
Range
Package
Type
E: -40OC to +85OC
E: SOT-2X
Number
of
Pins
Y: 6
Output Voltage
ADJ: Adjustable
Special Feature
Z: Lead free
7
AME
AME5142/5142A/5142B
High Efficiency 6 White LED Driver
With Open LED Protection
n Ordering Information
Part Number
Marking*
Output Voltage
Package
Operating Ambient
Temperature Range
AME5142AEEYADJZ
BJGww
ADJ
SOT-26
-40OC to +85OC
AME5142AEEYADJY
BJGww
ADJ
TSOT-26
-40OC to +85OC
AME5142AEEVADJZ
BJHww
ADJ
SOT-25
-40OC to +85OC
AME5142AEEVADJY
BJHww
ADJ
TSOT-25
-40OC to +85OC
AME5142AAEEYADJZ
BVKww
ADJ
SOT-26
-40OC to +85OC
AME5142AAEEYADJY
BVKww
ADJ
TSOT-26
-40OC to +85OC
AME5142BAEEYADJZ
BYPww
ADJ
SOT-26
-40OC to +85OC
AME5142BAEEYADJY
BYPww
ADJ
TSOT-26
-40OC to +85OC
AME5142AAEEVADJZ
BVLww
ADJ
SOT-25
-40OC to +85OC
AME5142AAEEVADJY
BVLww
ADJ
TSOT-25
-40OC to +85OC
Note: ww represents the date code and pls refer to Date Code Rule page on Package Dimension.
* A line on top of the first letter represents lead free plating such as BJGww.
Please consult AME sales office or authorized Rep./Distributor for the availability of package type.
8
Rev. C.02
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
n Absolute Maximum Ratings
Parameter
Symbol
Maximum
Unit
VIN
6
V
VEN ,VFB
VIN
V
VSW,VOVP
30
V
Input Supply Voltage
EN, FB Voltages
SW, OVP Voltage
B*
ESD Classification
Caution: Stress above the listed in absolute maximum ratings may cause permanent damage to the device.
* HBM B: 2000V ~ 3999V
n Recommended Operating Conditions
Parameter
Symbol
Rating
Ambient Temperature Range
TA
-40 to +85
Junction Temperature Range
TJ
-40 to +125
Storage Temperature Range
TSTG
-65 to +150
Unit
o
C
n Thermal Information
Parameter
Thermal Resistance*
(Junction to Case)
Thermal Resistance
(Junction to Ambient)
Package
SOT-25
TSOT-25
SOT-26
TSOT-26
Die Attach
Symbol
Maximum
θJC
81
Unit
o
C/W
Conductive Epoxy
Internal Power Dissipation
Solder Iron (10Sec)**
θJA
260
PD
400
350
mW
o
C
* Measure θJC on center of molding compound if IC has no tab.
** MIL-STD-202G 210F
Rev. C.02
9
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
n Electrical Specifications
VIN = 4.2V, EN = VIN, TA = 25oC, Unless otherwise noted.
Parameter
Input Voltage
Quiescent Current
Symbol
Test Condition
VIN
IQ
Min
Typ
2.7
Max
Units
5.5
V
Switching, VFB = 0V
0.85
1
mA
Not Switching, VFB = 0.2V
180
250
µA
Feedback Trip Point (AME5142)
VFB
0.137
0.15
0.163
V
Feedback Trip Point
(AME5142A/5142B)
VFB
0.094
0.104
0.114
V
FB Pin Bias Current
IFB
0.1
1
µA
Switch Current Limit
ICL
850
1000
mA
0.7
1.4
Ω
1
10
µA
1.5
MHz
Switch On-Resistance
RDSON
VFB = 0.2V
650
ISW = 100mA, VFB = 0.2V
SW Leakage Current
ISW
VSW = 20V
Swich frequency
fSW
VFB = 0.1V
0.9
1.2
Dmax
VFB = 0V
88
92
ISD
VEN = 0V
0.01
OTP
Shutdown, temperature increasing
160
TRS
Restore, temperature decreasing
140
Maximum Duty Cycle
Shutdown Supply Current
%
1
o
Over Temperature Protection
Over Voltage Protection
(AME5142)
10
OVP
Rising edge
Over Voltage Protection
(AME5142A/5142B)
OVP
Rising edge
Input Undervoltage Lockout
UVP
VIN rising or falling
EN Input Low
VEL
EN Input High
VEH
EN Input Current
IEN
24
26
µA
C
28
V
26
28
30
2.35
2.5
2.65
V
0.4
V
1.5
EN = GND or VIN
0.1
2
µA
Rev. C.02
AME
AME5142/5142A/5142B
High Efficiency 6 White LED Driver
With Open LED Protection
n Detailed Description
n Application Information
The AME5142/5142A/5142B is a constant frequency
step-up converter with an internal switch. The operations
of AME5142/5142A/5142B can be understood from block
diagram clearly figure.2. The oscillator triggers the SET
input of SR latch to turn on the power switch MS at the
start of each cycle. A current sense voltage sum with a
stabilizing ramp is connected to the positive terminal of
the PWM comparator. When this voltage exceeds the
output voltage of the error amplifier, the SR latch is reset
to turn off the power switch till next cycle starts. The
output voltage of the error amplifier is amplified from the
difference between the reference voltage 0.15V and the
feedback voltage. In this manner, if the error amplifiers
voltage increases, more current is delivered to the output; if it decreases, less current is delivered. A 28V Zener diode connects from OVP pin to FB pin internally to
provide an optional protection function which prevents SW
pin from over-voltage damage. Especially when the case
of the feedback loop broken due to component wear-out
or improper connection occurs.
Inductor Selection
Current Limit Protection
Schottky diode is a good choice for AME5142/5142A/
5142B because of its lower forward voltage drop and faster
reverse recovery. Using schottky diode can get better
efficiency. The high speed rectification is also a good
characteristic of schottky diode for high switching frequency. Current rating of the diode must meet the root
mean square of the peak current and output average current multiplication.
The AME5142/5142A/5142B has current limiting protection to prevent excessive stress on itself and external
components during overload conditions. The internal current limit comparator will disable the NMOS power device
at a typical switch peak current limit of 850mA.
Output Over-Voltage Protection
The AME5142/5142A/5142B contains dedicated circuitry for monitoring the output voltage. In the event that
the primary LED network is disconnected the output will
increase and be limited to 28V (TYP), which will turn the
NMOS off when the output voltage is at 28V (max.) until
the output voltage reach 28V (TYP.) or lower. The 28V
limit allows the use of 28V 1µF ceramic output capacitors
creating an overall small solution for white LED applications. If the output ever exceeds OVP, the AME5142B
will shut down. AME5142B will not switch again until the
power is recycled. If the output exceeds OVP, the OVP
of AME5142/5142A is to clamp the output voltage to 28V
typically.
The recommended value of inductor for AME5142/
5142A/5142B applications is 10µH. Small size and better efficiency are the major concerns for portable device,
such as AME5142/5142A/5142B used for dual panel
mobile phone. The inductor should have low DCR for
better efficiency. To avoid inductor saturation, current
rating should be at least 1A. The input range is 2.7V to
5.5V.
Capacitor Selection
4.7µF input capacitor can reduce input ripple. For better voltage stability, to increase the input capacitor value
or using LC filter is feasible, especially in the Li-ion battery application. 1µF output capacitor is sufficient to reduce output voltage ripple. For better voltage filtering,
ceramic capacitors with low ESR are recommended. X5R
and X7R types are suitable because of their wider voltage and temperature ranges.
Diode Selection
Duty Cycle
The maximum duty cycle of the switching regulator
determines the maximum boost ratio of output-toinput voltage that the converter can attain in mode of
operation. The duty cycle for a given boost application is
defined as: This applies for continuous mode operation.
D=
VOUT + VDIODE - V IN
VOUT + VDIODE - VSW
Under Voltage Protection
The AME5142/5142A/5142B has an UVP comparator
to turn the NMOS power device off in case the input voltage or battery voltage is too low preventing an on state of
the power device conducting large amounts of current.
Rev. C.02
11
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
Calculating Load Current
The load current is related to the average inductor current by the relation:
ILOAD = IIND (AVG) x (1 - D)
Where “ D” is the duty cycle of the application. The switch current can be found by:
ISW = IIND (AVG) + 1 /2 (IRIPPLE)
Inductor ripple current is dependent on inductance, duty cycle, input voltage and frequency:
IRIPPLE = D x (V IN-V SW) / (f x L)
Combining all terms, we can develop an expression which allows the maximum available load current to be calculated:
I LOAD
( 1-D ) x ( ICL (max) -
D ( VIN -V SW )
)
2fL
Thermal Considerations
At higher duty cycles, the increased ON time of the FET means the maximum output current will be determined by
power dissipation within the AME5142/5142A/5142B switch. The switch power dissipation from ON-state conduction is
calculated by:
P(SW) = D x IIND(AVE)2 x RDS(ON)
There will be some switching losses as well, so some derating needs to be applied when calculating IC power
dissipation.
Shutdown Pin Operation
The device is turned off by pulling the shutdown pin low. If this function is not going to be used, the pin should be tied
directly to VIN. If the SHDN function will be needed, a pull-up resistor must be used to VIN (approximately 50k-100k
recommended). The EN pin must not be left unterminated.
12
Rev. C.02
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
Evaluation Board Schematic
VDD
D1
L1
VLED_Anod
4.7uH 1A
30V_1A
C1
C2
U1
6
Enable
R1
4
2
IN
SW
EN
OVP
GND
FB
CF
1
5
VLED_cathode
3
AME5142AEEYADJZ
R2
Bill Of Materials
Location
Value
Description
Part Num.
Manufacture
Package
C1
6.3V/4.7uF
Ceramic Capacitor
C1608Y5V0J475ZT
TDK
1608
C7
25V/1uF
Ceramic Capacitor
C2012X7R1E105KT
TDK
2012
R1
51KΩ
Chip Resistor
FCR05-F-T-5102
PDC
805
R5
7.5Ω
Chip Resistor
FCR05-F-T-0750
PDC
805
R3
16.9KΩ
Chip Resistor
FCR05-F-T-1692
PDC
805
L1
4.7uH
Inductor
CDRH3D14/HP-4R7
Sumida
D1
30V/1A
Schottky Rectifier
B130
Any
Rev. C.02
SMA
13
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
Operating Instructions
1. Connect VDD to the power source’ s positive output.
2. Connect GND to supply ground.
3. Applying a logic signal to EN pin will enable the AME5142. Logic high (V EN>1.5V) turns on AME5142, logic low
puts it into low current shutdown mode.
Application Information
Setting Output Current
The regulated output current is set with an external resistor divider (R5 in Figure 1.) from the output to the VFB pin and
is determined by:
I OUT =
VFB
R5
To prevent stray capacitance and noises, locate resistors R5 close to AME5142.
The external resistor sets the output current table as below :
14
I OUT
R5
20mA
7.5Ω
40mA
3.75Ω
60mA
2.5Ω
80mA
1.875Ω
Rev. C.02
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
Board Layout Consideration
High frequency switching regulators require very careful layout of components in order to get stable operation
and low noise. A good PCB layout could make AME5142 work its best performance.
PCB Layout Example
The PCB layout example of AME5142 for six strings of LEDs to be driven in one parallel application. The
placements is suitable and smooth, and follows the layout guide lines.
1. Use a ground plane under the switching regulator to minimize inter-plane coupling.
2. Using 20mil wide track for GND (as wide as possible), and all GND nodes are as close as possible.
3. The SW node, schottky diode and output capacitor C2 signal path should be kept extremely short.
4. The feedback components R1,R2 and CF must be kept close to the FB pin of U1 to prevent noise injection
on the FB pin trace and keeping faraway from SW node.
VLED _Anode
SW
D1
Vout
GND
SW
IN
L1
IN
C1
U1
Vout
1 SW
6
IN
GND
2 GND
5 OVP
3
4
C2
CF Vo
VLED _Cathode
Rev. C.02
FB
FB
EN
EN
FB
GND R2
EN
Enable
R1
15
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
Dimming Control
A. Using a PWM Signal to EN Pin
For controlling the LED brightness, the AME5142/5142A/5142B can perform the dimming control by applying a PWM
signal to EN pin.
The average LED current is proportional to the PWM signal duty cycle. The magnitude of the PWM signal should be
higher than the maximum enable voltage of EN pin, in order to let the dimming control perform correctly.
L1
22µH
VIN 3.3V
CI N
4.7µF
VOUT
IN
Dimming
Control
150KHz
COUT
2.2µF
SW
AME5142
AME5142A
EN
AME5142B OVP
GND
FB
R1
7.5Ω
Figure 5. PWM Dimming Control Using the EN Pin
VFB VS Duty Cycle
IOUT VS Duty Cycle
20
150
18
125
16
14
I OUT(mA)
VFB(mV)
100
75
50
12
10
8
6
4
25
2
0
0.2
0.4
0.6
Duty Cycle
16
0.8
0
0.2
0.4
0.6
0.8
Duty Cycle
Rev. C.02
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
B. Using a DC Voltage
Using a variable DC voltage to adjust the brightness is a popular method in some applications. The dimming control
using a DC voltage circuit is shown in Figure 6. According to the Superposition Theorem, as the DC voltage increases,
the voltage contributed to VFB increases and the voltage drop on R2 decreases, i.e. the LED current decreases. For
example, if the VDC range is from 0V to 2.8V, the selection of resistors in Figure 6 sets dimming control of LED current
from 20mA to 0mA.
L1
10µH
VIN 2.7V to 5.5V
C IN
4.7µF
VOUT
IN
COUT
1µF
SW
AME5142
AME5142A
EN
OVP
AME5142B
R3
5.1K
FB
GND
R4
91K
R2
7.5Ω
VDC Dimming
0V to 2.8V
Figure 6. Dimming Control Using a DC Voltage
VFB VS VDC
IOUT VS VDC
20
150
125
15
IOUT(mA)
VFB(mV)
100
75
10
50
5
25
0
0
0
0.56
1.12
1.68
VDC(V)
Rev. C.02
2.24
2.80
0
0.56
1.12
1.68
2.24
2.80
VDC(V)
17
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
C. Using a Filtered PWM Signal
The filtered PWM signal can be considered as an adjustable DC voltage. It can be used to replace the variable DC
voltage source in dimming control. The circuit is shown in Figure 7.
L1
10µH
VIN 2.7V to 5.5V
C IN
4.7µF
VOUT
IN
COUT
1µF
SW
AME5142
AME5142A
EN
OVP
AME5142B
R3
5.1K
FB
GND
R4
91K
R2
7.5Ω
CDC
1µF
R DC
10K
2.8V
0V
PWM Signal
20KHZ
Figure 7. Dimming Control Using a Filtered PWM Signal
IOUT VS Duty Cycle
VFB VS Duty Cycle
20
150
125
15
IOUT(mA)
VFB(mV)
100
75
10
50
5
25
0
0
0
0.2
0.4
0.6
Duty Cycle
18
0.8
1
0
0.2
0.4
0.6
0.8
1
Duty Cycle
Rev. C.02
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
n Typical Operating Characteristics
L1
10µH
VIN 2.7V to 5.5V
CIN
4.7µF
Efficiency Vs IOUT
VOUT
IN
90
COUT
1µF
SW
85
GND
Efficiency (%)
AME5142
AME5142A
EN
OVP
AME5142B
FB
R2
7.5Ω
VIN = 3.6V
VIN = 4.2V
80
VIN = 3.3V
75
VIN = 2.7V
70
65
60
I LED = 20mA
55
Figure 8: Circuit For Driving 6 White LEDs
V OUT =18.6V
50
0
5
10
15
20
IOUT(mA)
L1
10µH
VIN 3.3V to 5.5V
CIN
4.7µF
Efficiency Vs VIN
VOUT
IN
100
C OUT
1µF
SW
AME5142
AME5142A
EN
AME5142B OVP
Efficiency (%)
GND
95
FB
R2
7.5Ω
R2
7.5Ω
90
85
I OUT = 40mA
VOUT = 9.3V
80
Figure 9: Circuit For Driving 2 Strings of 3 White LEDs
3
3.5
4
4.5
5
5.5
VIN(v)
L1
10µH
VIN 3.3V to 5.5V
90
IN
C OUT
1µF
SW
AME5142
AME5142A
EN
AME5142B OVP
GND
FB
R2
7.5Ω
R2
7.5Ω
85
Efficiency (%)
CIN
4.7µF
Efficiency Vs IOUT
VOUT
VIN = 3.3V
80
75
VIN = 3.6V
70
65
60
VIN = 4. 2V
I LED = 20mA
55
Figure 10: Circuit For Driving 2 Strings of 3 White LEDs
50
0
V OUT = 9.3V
10
20
30
40
I OUT (mA)
Rev. C.02
19
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
L1
10µH
VIN 3.3V to 5.5V
CIN
4.7µF
Efficiency Vs VIN
VOUT
IN
100
COUT
1µF
SW
GND
Efficiency (%)
AME5142
AME5142A
EN
AME5142BOVP
FB
R2
7.5Ω
95
90
85
R2
7.5Ω
IOUT = 40mA
VOUT = 12.5V
80
3
Figure 11: Circuit For Driving 2 Strings of 4 White LEDs
3. 5
4
4.5
5
5.5
VIN (v)
L1
10µH
VIN 3.3V to 5.5V
CIN
4.7µF
Efficiency Vs IOUT
VOUT
90
IN
COUT
1µF
SW
AME5142
AME5142A
EN
AME5142BOVP
VIN = 3.3V
80
Efficiency (%)
GND
85
FB
R2
7.5Ω
R2
7.5Ω
75
70
VIN = 3.6V
65
VIN = 4.2V
60
ILED = 20mA
55
VOUT =12.5V
50
Figure 12: Circuit For Driving 2 Strings of 4 White LEDs
0
10
20
30
40
IOUT (mA)
L1
10µH
VIN 3.3V to 5.5V
IN
COUT
1µF
SW
AME5142
AME5142A
EN
AME5142BOVP
GND
100
Efficiency (%)
CIN
4.7µF
Efficiency Vs VIN
VOUT
FB
R2
7.5Ω
R2
7.5Ω
95
90
85
IOUT = 40mA
VOUT = 15.6V
80
Figure 13: Circuit For Driving 2 Strings of 5 White LEDs
20
3
3.5
4
4. 5
5
5.5
VIN(v)
Rev. C.02
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
L1
10µH
VIN 3.3V to 5.5V
Efficiency Vs IOUT
VOUT
90
CIN
4.7µF
IN
SW
FB
R2
7.5Ω
R2
7.5Ω
VIN = 3.3V
85
Efficiency (%)
AME5142
AME5142A
EN
AME5142BOVP
GND
VIN = 3.6V
COUT
1µF
80
VIN = 4.2V
75
70
65
60
ILED = 20mA
55
50
Figure 14: Circuit For Driving 2 Strings of 5 White LEDs
VOUT =15.6V
0
10
20
30
40
IOUT (mA)
L1
10µH
VIN 3.3V to 5.5V
Efficiency Vs VIN
VOUT
100
CIN
4.7µF
IN
COUT
1µF
SW
GND
Efficiency (%)
AME5142
AME5142A
EN
AME5142BOVP
FB
R2
7.5Ω
R2
7.5Ω
95
90
85
IOUT = 40mA
VOUT = 18.6V
80
3
Figure 15: Circuit For Driving 2 Strings of 6 White LEDs
3.5
4
4.5
5
5.5
VI N(v)
L1
10µH
VIN 3.3V to 5.5V
Efficiency Vs IOUT
VOUT
90
IN
COUT
1µF
SW
AME5142
AME5142A
EN
AME5142BOVP
GND
FB
R2
7.5Ω
R2
7.5Ω
85
VIN = 3.3V
Efficiency (%)
CIN
4.7µF
80
75
70
65
60
VIN = 4.2V
VIN = 3.6V
ILED = 20mA
55
Figure 16: Circuit For Driving 2 Strings of 6 White LEDs
Rev. C.02
50
0
VOUT =18.6V
10
20
30
40
IOUT(mA)
21
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
n Characterization Curves
92.0
91.8
91.6
91.4
91.2
91.0
90.8
90.6
90.4
90.2
90.0
89.8
89.6
89.4
89.2
89.0
88.8
88.6
88.4
88.2
88.0
-25
Oscillator Frequency vs. Temperature
1.50
Oscillator Frequency (MHz)
Max Duty Cycle (%)
Max Duty Cycle vs. Temperature
0
25
50
75
o
100
125
1.45
1.40
1.35
1.30
1.25
1.20
1.15
1.10
1.05
1.00
0.95
0.90
-25
0
25
50
75
100
Temperature ( C)
Temperature ( oC)
Switch RDSON
Efficiency vs. Load Current
Dirving 3 LEDs
125
100
1.80
1.60
90
1.20
Efficiency (%)
RDSON (Ω)
1.40
TA = 85oC
1.00
0.80
TA = 25oC
0.60
80
70
60
0.40
3.1
3.5
3.9
4.3
4.7
5.1
3.5
3.9
4.3
4.7
5.1
VIN (V)
Efficiency vs. Load Current
Dirving 4 LEDs
Efficiency vs. Load Current
Dirving 6 LEDs
100
100
90
90
80
70
50
2.7
3.1
VIN (V)
60
22
50
2.7
5.5
Efficiency (%)
Efficiency (%)
0.20
2.7
5.5
80
70
60
3.1
3.5
3.9
4.3
VI N (V)
4.7
5.1
5.5
50
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
VIN (V)
Rev. C.02
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
Current Limit vs. VIN
VFB vs. Temperature
1000
0.177
0.173
0.169
900
0.165
VFB (V)
Current Limit (mA)
950
850
800
0.161
0.157
0.153
750
0.149
0.145
700
0.141
650
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
0.137
-25
25
50
75
100
125
Temperature (oC)
Dimming Control for Driving 6LEDs
Dimming Control for Driving 6LEDs
2
2
3
3
1
1
1mS / div
Rev. C.02
0
VIN (V)
1mS / div
VIN = 2.7V; 6 LEDs
IOUT = 20mA
VIN = 5.5V; 6 LEDs
IOUT = 20mA
2) EN = 1V / div, DC f = 200Hz
3) VOUT , 10V / div, DC
1) VSW= 10V / div, DC
2) EN = 1V / div, DC f = 200Hz
3) VOUT , 10V / div, DC
1) VSW = 10V / div, DC
23
AME
AME5142/5142A/5142B
High Efficiency 6 White LED Driver
With Open LED Protection
Dimming Control for Driving 6LEDs
Dimming Control for Driving 6LEDs
2
2
3
3
1
1
4µS / div
4µS / div
VIN = 2.7V; 6 LEDs
IOUT = 20mA
VIN = 5.5V; 6 LEDs
IOUT = 20mA
2) EN = 1V / div, DC f = 200KHz
3) VOUT , 10V / div, DC
1) VSW = 10V / div, DC
2) EN = 1V / div, DC f = 200KHz
3) VOUT , 10V / div, DC
1) VSW = 10V / div, DC
Start-Up / Shutdown
Start-Up / Shutdown
1
1
2
2
3
3
200µS / Div
24
200µS / div
VIN = 2.7V; 1 LEDs
IOUT = 20mA
VIN = 2.7V; 6 LEDs
IOUT = 20mA
1) EN = 2V/div, DC
2) Inductor Current, 100mA / div, DC
3) VOUT , 2V / div, DC
1) EN = 2V / div, DC
2) Inductor Current, 500mA / div, DC
3) VOUT , 10V / div, DC
Rev. C.02
AME
AME5142/5142A/5142B
High Efficiency 6 White LED Driver
With Open LED Protection
Start-Up / Shutdown
Typical Switching Waveform
1
1
2
2
3
3
1µS / div
200µS / div
VIN = 5.5V; 6 LEDs
IOUT = 20mA
VIN = 2.7V; 6 LEDs
IOUT = 20mA
1) EN = 2V / div, DC
2) Inductor Current, 500mA / div, DC
3) VOUT , 10V / div, DC
1) VSW = 10V / div, DC
2) VOUT , 20mV / div, AC
3) Input Current, 100mA / div, DC
Inductor = 10µH, COUT = 1µF
Typical Switching Waveform
Start up into Openload
AME5142B
1
1
2
3
3
2
1µS / div
VIN = 5.5V; 6 LEDs
IOUT = 20mA
100µS / div
1) VEN = 2V / div
2) VSW, 10V / div
3) VOUT , 10V / div
1) VSW = 10V / div, DC
2) VOUT , 20mV / div, AC
3) Input Current, 100mA / div, DC
Inductor = 10µH, COUT = 1µF
Rev. C.02
25
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
n Date Code Rule
Marking
Date Code
Year
A
A
A
W
W
xxx0
A
A
A
W
W
xxx1
A
A
A
W
W
xxx2
A
A
A
W
W
xxx3
A
A
A
W
W
xxx4
A
A
A
W
W
xxx5
A
A
A
W
W
xxx6
A
A
A
W
W
xxx7
A
A
A
W
W
xxx8
A
A
A
W
W
xxx9
n Tape and Reel Dimension
SOT-25
P
W
AME
AME
PIN 1
Carrier Tape, Number of Components Per Reel and Reel Size
26
Package
Carrier Width (W)
Pitch (P)
Part Per Full Reel
Reel Size
SOT-25
8.0±0.1 mm
4.0±0.1 mm
3000pcs
180±1 mm
Rev. C.02
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
n Tape and Reel Dimension
TSOT-25
P
W
AME
AME
PIN 1
Carrier Tape, Number of Components Per Reel and Reel Size
Package
Carrier Width (W)
Pitch (P)
Part Per Full Reel
Reel Size
TSOT-25
8.0±0.1 mm
4.0±0.1 mm
3000pcs
180±1 mm
SOT-26
P
W
AME
AME
PIN 1
Carrier Tape, Number of Components Per Reel and Reel Size
Rev. C.02
Package
Carrier Width (W)
Pitch (P)
Part Per Full Reel
Reel Size
SOT-26
8.0±0.1 mm
4.0±0.1 mm
3000pcs
180±1 mm
27
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
n Tape and Reel Dimension
TSOT-26
P
W
AME
AME
PIN 1
Carrier Tape, Number of Components Per Reel and Reel Size
28
Package
Carrier Width (W)
Pitch (P)
Part Per Full Reel
Reel Size
TSOT-26
8.0±0.1 mm
4.0±0.1 mm
3000pcs
180±1 mm
Rev. C.02
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
n Package Dimension
SOT-25
Top View
Side View
SYMBOLS
E
H
D
L
S1
PIN 1
MAX
MIN
MAX
A
0.90
1.30
0.0354
0.0512
A1
0.00
0.15
0.0000
0.0059
b
0.30
0.55
0.0118
0.0217
D
2.70
3.10
0.1063
0.1220
E
1.40
1.80
0.0551
0.0709
1.90 BSC
e
2.60
θ1
0
3.00
o
0.10236 0.11811
0.0146BSC
o
10
0
o
10
o
0.95BSC
0.0374BSC
MILLIMETERS
INCHES
S1
A1
A
0.07480 BSC
0.37BSC
L
Front View
INCHES
MIN
H
e
MILLIMETERS
b
TSOT-25
Top View
Side View
SYMBOLS
E
H
D
MIN
MAX
MIN
MAX
A+A1
0.90
1.25
0.0354
0.0492
b
0.30
0.50
0.0118
0.0197
D
2.70
3.10
0.1063
0.1220
E
1.40
1.80
0.0551
0.0709
1.90 BSC
e
L
PIN 1
S1
H
2.40
θ1
Front View
0
o
0.1181
0.0138BSC
o
10
0.95BSC
0.0945
0
o
10
o
0.0374BSC
A1
A
S1
3.00
0.35BSC
L
e
0.07480 BSC
b
Rev. C.02
29
AME
High Efficiency 6 White LED Driver
With Open LED Protection
AME5142/5142A/5142B
n Package Dimension
SOT-26
Top View
Side View
SYMBOLS
E
H
D
e
MILLIMETERS
L
MIN
MAX
MIN
MAX
A
0.90
1.30
0.0354
0.0512
A1
0.00
0.15
0.0000
0.0059
b
0.30
0.55
0.0118
0.0217
D
2.70
3.10
0.1063
0.1220
E
1.40
1.80
0.0551
0.0709
1.90 BSC
e
PIN1
S1
H
2.60
A
θ1
0.07480 BSC
3.00
0.37BSC
L
Front View
INCHES
0
o
0.10236 0.11811
0.0146BSC
10
o
0
o
10
0.95BSC
0.0374BSC
MILLIMETERS
INCHES
A1
S1
o
b
TSOT-26
Top View
Side View
SYMBOLS
E
H
D
e
L
PIN1
MIN
MAX
MIN
MAX
A+A1
0.90
1.25
0.0354
0.0492
b
0.30
0.50
0.0118
0.0197
D
2.70
3.10
0.1063
0.1220
E
1.40
1.80
0.0551
0.0709
H
S1
1.90 BSC
e
2.40
θ1
A
0
o
10
0.95BSC
0.0945
0.1181
0.0138BSC
o
0
o
10
o
0.0374BSC
A1
S1
3.00
0.35BSC
L
Front View
0.07480 BSC
b
30
Rev. C.02
www.ame.com.tw
E-Mail: sales@ame.com.tw
Life Support Policy:
These products of AME, Inc. are not authorized for use as critical components in life-support
devices or systems, without the express written approval of the president
of AME, Inc.
AME, Inc. reserves the right to make changes in the circuitry and specifications of its devices and
advises its customers to obtain the latest version of relevant information.
 AME, Inc. , April 2009
Document: 1229-DS5142/5142A/5142B-C.02
Corporate Headquarter
AME, Inc.
2F, 302 Rui-Guang Road, Nei-Hu District
Taipei 114, Taiwan.
Tel: 886 2 2627-8687
Fax: 886 2 2659-2989