AP8802H [DIODES]
60V 1A LED Step-down Converter; 60V 1A LED降压转换器型号: | AP8802H |
厂家: | DIODES INCORPORATED |
描述: | 60V 1A LED Step-down Converter |
文件: | 总11页 (文件大小:190K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
AP8802H
60V 1A LED Step-down Converter
Description
Pin Assignments
The AP8802H is a step-down DC/DC converter designed to
drive LEDs with a constant current. The device can drive up
to thirteen LEDs, depending on the forward voltage of the
LEDs, in series from a voltage source of 8V to 60V. Series
connection of the LEDs provides identical LED currents
resulting in uniform brightness and eliminating the need for
ballast resistors. The AP8802H switches at frequency up to
500kHz. This allows the use of small size external
components, hence minimizing the PCB area needed.
(Top View)
SET 1
8
7
6
5
CTRL
GND
SW
2
GND
NC 3
VIN
AP8802H
4
SW
SO-8-EP
Maximum output current of AP8802H is set via an external
resistor connected between the VIN and SET input pins.
Dimming is achieved by applying either a DC voltage or a
PWM signal at the CTRL input pin. An input voltage of 0.2V
or lower at CTRL shuts down the output at SW and puts the
device into a low-current standby state.
Applications
•
•
•
•
Commercial & industrial lighting
Small LCD panel backlight
Appliances interior lighting
Architecture Detail lighting
Features
•
•
•
•
•
•
•
•
LED driving current up to 1A
High efficiency up to 92%
Operating input voltage up to 60V
5% nominal accuracy
High switching frequency up to 500kHz
PWM/DC input for dimming control
Built-in output open-circuit protection
SO-8-EP is available in “Green” Molding Compound
(No Br, Sb)
•
Lead Free Finish/ RoHS Compliant (Note 1)
Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at
http://www.diodes.com/products/lead_free.html.
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© Diodes Incorporated
AP8802H
Document number: DS32227 Rev. 1 - 2
AP8802H
60V 1A LED Step-down Converter
Typical Application Circuit
48V
VIN
CTRL
RSET = 0.2 ohm
SET
1
D1
AP8802H
C1 = 2.2µF
L1 = 100µH
GND
SW
Pin Descriptions
Pin Name
Description
Switch Pin. Connect inductor/freewheeling diode here, minimizing track length at this pin to
reduce EMI.
SW
GND
SET
GND pin
Set Nominal Output Current Pin. Configure the output current of the device.
Dimming and On/Off Control Input. Input voltage of 0.2V or lower forces the device into low
current standby mode and shuts off the output. A PWM signal allows the output current to be
adjusted above or below the level set by the resistor connected to SET input pin.
CTRL
The input impedance is about 50kΩ, and if the pin is left open VCTRL = VREF
Input Supply Pin. Must be locally bypassed.
No connection
VIN
NC
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AP8802H
Document number: DS32227 Rev. 1 - 2
AP8802H
60V 1A LED Step-down Converter
Functional Block Diagram
SET
SW
V
IN
Sensing
Block
Voltage
Regulator
5V
PWM/DC
Control
CTRL
GND
R
VREF 1.25V
AP8802H
Figure 2: AP8802H Block Diagram
Absolute Maximum Ratings
Symbol
Parameter
Rating
-0.3~60
-0.3~60
150
Unit
V
VIN
VSW
TJ
VIN pin Voltage
SW Voltage
V
Junction Temperature
°C
°C
°C
TLEAD
TST
Lead Temperature Soldering
Storage Temperature Range
300
-65 to +150
Caution: The absolute maximum ratings are rated values exceeding which the product could suffer physical damage. These values must therefore not be
exceeded under any condition.
Semiconductor devices are ESD sensitive and may be damaged by exposure to ESD events. Suitable ESD precautions should be taken when
handling and transporting these devices.
Recommended Operating Conditions (Note 2)
Symbol
Parameter
Ambient Temperature Range
Min
-40
0.1
Max
105
Unit
TA
ºC
Duty Cycle Using Inductor ≥ 100µH (Note 2)
0.95
Notes:
2. For most applications the LED current will be within 5% over the duty cycle range specified. Duty cycle accuracy is also dependent on
propagationdelay. Smaller size inductors can be used but LED current accuracy may be greater than 5% at extremes of duty cycle. This is most
noticeable at low duty cycles (less than 0.1) or when the input voltage is high and only one LED is being driven.
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© Diodes Incorporated
AP8802H
Document number: DS32227 Rev. 1 - 2
AP8802H
60V 1A LED Step-down Converter
Electrical Characteristics (VIN =12V, TA=25oC, unless otherwise specified)
Symbol
VIN
Parameter
Conditions
Min
Typ.
Max Unit
Operating Input Voltage
Continuous switch current
Quiescent Current
8.0
-
60
1
V
A
IOUT
(Note 3)
IQ
-
75
120
0.5
210
-
μA
MHz
mV
V
FOSC
VTHD
VREF
SET
Rds(on)
Switching Frequency
-
-
Internal Threshold Voltage
Internal Reference Voltage
SET pin input current
190
200
-
-
1.25
VSET = VIN-0.2
ISW = 0.8A
5
-
μA
Ω
On Resistance of MOSFET
0.65
1.1
8
ISW_Leakage Switch leakage current
-
1.25
-
-
-
-
μA
V
EN
EN
Voltage High
Voltage Low
ON
-
OFF
0.2
V
Thermal Resistance Junction-
to-Ambient
SO-8-EP (Note 4)
SO-8-EP (Note 4)
-
-
45
7
-
-
θJA
θJC
°C/W
°C/W
Thermal Resistance Junction-
to-Case
Notes:
3. Refer to figure 8 for the device derating curve.
4. Test condition for SO-8-EP: Device mounted on FR-4 PCB, 2”x2”, 2oz copper, minimum recommended pad layout on top layer and thermal vias to
bottom layer ground plane. For better thermal performance, larger copper pad for heat-sink is needed.
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© Diodes Incorporated
AP8802H
Document number: DS32227 Rev. 1 - 2
AP8802H
60V 1A LED Step-down Converter
Applications Information
LED Current Control
The LED current is controlled by the resistor RSET in Figure 1 connected between VIN and SET. The nominal
average output current in the LED(s) is defined as:
V
THD
I
=
LED
R
SET
If the CTRL pin is driven by an external voltage (lower than 2.5V), the average LED current is:
V
V
CTRL THD
I
=
LED
V
R
REF
SET
LED current Versus RSET and VCTRL
1200
1000
800
600
400
200
0
0.39
0.2
0.2
LED current @
VCTRL = 1.25V
0.47
0.56
LED current @
VCTRL = 2.5V
0.33
0.39
0.47
0.56
0.68
0.82
LED current @
VCTRL = 0.625V
1
1.2
1.5
0.68
0.33
0.82
0.82
1
1
2
0.47
1.2
1.5
2
0.68
3
3
3
1.2
1.5
2
0
0.15 0.3 0.45 0.6 0.75 0.9 1.05 1.2 1.35 1.5 1.65 1.8 1.95 2.1 2.25 2.4 2.55 2.7 2.85
3
RSET value [Ohms]
Figure 3: LED Current setting Vs RSET and VCTRL
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AP8802H
Document number: DS32227 Rev. 1 - 2
AP8802H
60V 1A LED Step-down Converter
Applications Information (Continued)
Inductor Selection
This section highlights how to select the inductor suitable for the application requirements in terms of switching
frequency, LED current accuracy and temperature.
Switching Frequency @ILED = 700mA
500
68
450
400
100
47
350
300
250
200
150
100
50
12V - 3 LEDs
24V - 5 LEDs
48V - 10 LEDs
68
68
150
100
100
220
150
150
47
470
220
220
470
470
0
0
50
100
150
200
250
300
350
400
450
500
Inductor Value [uH]
Figure 4: Switching Frequency Vs Inductor Value
The inductor influences the LED current accuracy that the system is able to provide. The following section
highlights how to select the inductor in relation to the device packages and the LED current, while maintaining the
chip temperature below 70˚C.
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AP8802H
Document number: DS32227 Rev. 1 - 2
AP8802H
60V 1A LED Step-down Converter
Applications Information (Continued)
AP8802H SO-8-EP Minimum Recommended Inductor
15
14
13
12
11
10
9
Legend
47µH
5% Accuracy,
TC < 70°C
ILED ~ 1A
68µH
100µH
150µH
8
7
6
150µH
5
68µH
100µH
4
47µH
3
2
1
0
10
20
30
40
50
60
Supply Voltage (V)
Figure 5: SO-8-EP recommended inductor with 1A LED current
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AP8802H
Document number: DS32227 Rev. 1 - 2
AP8802H
60V 1A LED Step-down Converter
Applications Information (Continued)
Capacitor Selection
The small size of ceramic capacitors makes them ideal for AP8802H applications. X5R and X7R types are
recommended because they retain their capacitance over wider voltage and temperature ranges than other types
such as Z5U. A 2.2μF input capacitor is sufficient for most intended applications of AP8802H.
A 4.7μF input capacitor is suggested for application with an input voltage equal or higher than 60V.
Diode Selection
Schottky diodes, e.g. B2100 or B1100, with their low forward voltage drop and fast reverse recovery, are the ideal
choice for AP8802H applications.
PWM Dimming
A Pulse Width Modulated (PWM) signal with a max resolution of 8bit, can be applied to the CTRL pin to change
the output current to a value above or below the nominal average value set by resistor RSET. To achieve this
resolution the PWM frequency has to be lower than 500Hz.
Thermal Considerations
The graph below in figure 8, gives details for power derating. This assumes the device to be mounted on a
25x25mm PCB with 1oz copper standing in still air.
Maximum Power Dissipation
2.4
2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0
25
50
75
100
125
Ambient temperature (°C)
Figure 8: AP8802H Derating Curves
Package Selection
The device comes with a wide selection of packages. The suggested package is able to provide a case
temperature below 70˚C (with an ambient temperature of 25˚C) for the combination of input voltage and load
requested.
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© Diodes Incorporated
AP8802H
Document number: DS32227 Rev. 1 - 2
AP8802H
60V 1A LED Step-down Converter
Ordering Information
AP8802H SP - 13
Packing
Package
SP : SO-8-EP
13 : Tape & Reel
13” Tape and Reel
Package
Code
Packaging
(Note 5)
Device
Quantity
Part Number Suffix
AP8802HSP-13
SP
SO-8-EP
2500/Tape & Reel
-13
Notes: 5. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at
http://www.diodes.com/datasheets/ap02001.pdf.
Marking Information
(1) SO-8-EP
( Top View )
5
8
A~Z : Internal code
Logo
YY : Year : 08, 09,10~
WW : Week : 01~52; 52
Part No.
AP8802H
E
YYWWX X
represents 52 and 53 week
X : Internal Code
SO-8-EP
1
4
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© Diodes Incorporated
AP8802H
Document number: DS32227 Rev. 1 - 2
AP8802H
60V 1A LED Step-down Converter
Package Outline Dimensions (All Dimensions in mm)
(1) Package Type: SO-8-EP
Detail "A"
7°~9°
Exposed pad
45°
1
1
7°~9°
0.15/0.25
3.3Ref.
Bottom View
0.3/0.5
1.27typ
Gauge Plane
Seating Plane
4.85/4.95
0.62/0.82
1
Detail "A"
8x-0.60
Exposed pad
6x-1.27
Land Pattem Recommendation
(Unit:mm)
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© Diodes Incorporated
AP8802H
Document number: DS32227 Rev. 1 - 2
AP8802H
60V 1A LED Step-down Converter
IMPORTANT NOTICE
DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS
DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).
Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other
changes without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability
arising out of the application or use of this document or any product described herein; neither does Diodes Incorporated convey any
license under its patent or trademark rights, nor the rights of others. Any Customer or user of this document or products described
herein in such applications shall assume all risks of such use and will agree to hold Diodes Incorporated and all the companies
whose products are represented on Diodes Incorporated website, harmless against all damages.
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sales channel.
Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall
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arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.
Products described herein may be covered by one or more United States, international or foreign patents pending. Product names
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LIFE SUPPORT
Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without
the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body, or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided
in the labeling can be reasonably expected to result in significant injury to the user.
B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected
to cause the failure of the life support device or to affect its safety or effectiveness.
Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or
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concerning their products and any use of Diodes Incorporated products in such safety-critical, life support devices or systems,
notwithstanding any devices- or systems-related information or support that may be provided by Diodes Incorporated. Further,
Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes
Incorporated products in such safety-critical, life support devices or systems.
Copyright © 2010, Diodes Incorporated
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© Diodes Incorporated
AP8802H
Document number: DS32227 Rev. 1 - 2
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