AL8808 반도체 회로 부품 판매점
COST EFFECTIVE LOW EMI 30V 1A BUCK LED DRIVER
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 Diodes |
AL8808
COST EFFECTIVE LOW EMI 30V 1A BUCK LED DRIVER
Description
The AL8808 is a step-down DC/DC converter designed to drive LEDs
with a constant current. The device can drive up to 8 LEDs,
depending on the forward voltage of the LEDs, in series from a
voltage source of 6V to 30V. Series connection of the LEDs provides
identical LED currents resulting in uniform brightness and eliminating
the need for ballast resistors. The AL8808 switches at frequency up to
1MHz with controlled rise and fall times to reduce EMI. This allows
the use of small size external components, hence minimizing the PCB
area needed.
Maximum output current of AL8808 is set via an external resistor
connected between the VIN and SET input pins. Dimming is achieved
by applying either an analog DC voltage or a PWM signal at the
CTRL input pin. An input voltage of 0.4V or lower at CTRL switches
off the output MOSFET simplifying PWM dimming.
Applications
• MR16 Lamps
• General Illumination Lamps
Pin Assignments
(Top View)
SW 1
GND 2
5 VIN
CTRL 3
4 SET
TSOT25
Features
• LED Driving Current Up to 1A
• Better Than 5% Accuracy
• High Efficiency Up to 96%
• Fast Controlled Falling Edges 7ns
• Operating Input Voltage from 6V to 30V
• High Switching Frequency Up to 1MHz
• PWM/DC Input for Dimming Control
• Built-In Output Open-Circuit Protection
• Built-In Over-Temperature Protection
• TSOT25: Available in “Green” Molding Compound (No Br, Sb)
Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
Halogen and Antimony Free. “Green” Device (Note 3)
Notes:
1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.
2. See http://www.diodes.com for more information about Diodes Incorporated’s definitions of Halogen and Antimony free, "Green" and Lead-Free.
3. Halogen and Antimony free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl)
and <1000ppm antimony compounds.
Typical Applications Circuit
AL8808
Document number: DS35648 Rev. 2 - 2
1 of 20
www.diodes.com
January 2013
© Diodes Incorporated
AL8808
Pin Descriptions
Pin Number
1
2
Pin Name
SW
GND
3 CTRL
4 SET
5 VIN
Function
Switch Pin. Connect inductor/freewheeling diode here, minimizing track length at this pin to reduce EMI.
GND Pin
Dimming and On/Off Control Input.
• Leave floating for normal operation.
(VCTRL = 5V, Gives nominal average output current IOUTnom = 0.1/RS)
• Drive to voltage below 0.4V to turn off output current
• Drive with an analog voltage (0.5V < VCTRL < 2.5V) to adjust output current from 20% to 100% of
IOUTnom
• Drive with an analog voltage > 2.6V output current will be 100% of IOUTnom
• A PWM signal (low level ≤ 0.4V and high level > 2.6; transition times less than 1µs) allows the output
current to be adjusted below the level set by the resistor connected to SET input pin.
Set Nominal Output Current Pin. Configure the output current of the device.
Input Supply Pin. Must be locally decoupled to GND with > 2.2µF X7R ceramic capacitor – see applications
section for more information.
Functional Block Diagram
Figure 1. AL8808 Block Diagram
Absolute Maximum Ratings (@TA = +25°C, unless otherwise specified.)
Symbol
ESD HBM
ESD MM
VIN
VSET
VSW
VCTRL
ISW
TJ
TLEAD
TST
Parameter
Human Body Model ESD Protection
Machine Model ESD Protection
Continuous VIN pin voltage relative to GND
SET pin voltage relative to VIN pin
SW voltage relative to GND
CTRL pin input voltage
Switch current
Junction Temperature
Lead Temperature Soldering
Storage Temperature Range
Ratings
2.5
200
-0.3 to +33
-5 to +0.3
-0.3 to +33
-0.3 to +6
1.25
150
300
-55 to +150
Unit
kV
V
V
V
V
V
A
°C
°C
°C
Caution:
Stresses greater than the 'Absolute Maximum Ratings' specified above, may cause permanent damage to the device. These are stress ratings only;
functional operation of the device at these or any other conditions exceeding those indicated in this specification is not implied. Device reliability may be
affected by exposure to absolute maximum rating conditions for extended periods of time.
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.
AL8808
Document number: DS35648 Rev. 2 - 2
2 of 20
www.diodes.com
January 2013
© Diodes Incorporated
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AL8808 led
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국내 전력반도체 판매점
상호 : 아이지 인터내셔날
전화번호 : 051-319-2877
[ 홈페이지 ]
IGBT, TR 모듈, SCR, 다이오드모듈, 각종 전력 휴즈
( IYXS, Powerex, Toshiba, Fuji, Bussmann, Eaton )
전력반도체 문의 : 010-3582-2743
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