AL1678-20B Datasheet, PDF (1/13 Pages) Diodes Incorporated – UNIVERSAL, 500V BUCK LED DRIVER

AL1678-20B/10B/08B
UNIVERSAL, 500V BUCK LED DRIVER
Description
The AL1678-20B/10B/08B is a universal AC input (85 to 277 VAC),
high efficiency and high accuracy Buck LED driver. The AL1678-
20B/10B/08B topology provides accurate constant current over line
and load regulation with tight tolerance ±3%, operating at boundary
conduction mode (BCM) to ease in EMI/EMC qualification and testing
to meet the latest regulatory laws.
The AL1678-20B/10B/08B single Buck stage system works with a
single winding inductor and High voltage MOSFET included,
therefore, can use fewer external components and create a low bill of
material (BOM) cost solution. The AL1678-20B/10B/08B has rich
protection features to enhance the system safety and reliability. It has
thermal fold back function, which can reduce the output current when
the driver’s temperature is higher than the setting value.
The AL1678-20B/10B/08B is available in SO-7 package.
Features
 > 90% Efficiency
 Valley Switching to Achieve Low Switching Loss
 Universal 85 to 277 VAC Input Range
 Internal MOSFET up to 500V
 Tight Current Sense Tolerance: ±3%
 Low Start-up Current: 170µA
 Low Operation Current: 100µA (Static)
 Single Winding Inductor
 Internal Protections
 Under Voltage Lock Out (UVLO)
 Leading-edge Blanking (LEB)
 Output Open/Short Protection
 Open-load and Reload Detection
 Thermal Fold-back Function
 Over Temperature Protection (OTP)
 SO-7 Package
 Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
 Halogen and Antimony Free. “Green” Device (Note 3)
Pin Assignments
(Top View)
OUT 1
VCC 2
ROVP 3
GND 4
7 Drain
6 LC
5 CS
SO-7
Applications
 Retrofit LED Lamps
 High Voltage DC-DC LED Driver
 General Purpose Constant Current Source
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/quality/lead_free.html 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
AC
Input
F1
DB1
C1
R1
D1
R4
C3
+
OUT
L1
R2
R3
C2
1 OUT Drain ⁷
2 _VCC
3
ROVP
LC ⁶
4 _{GND CS} 5
U1 AL1678-20B/10B/08B _R5
AL1678-20B/10B/08B
Document number: DS37637 Rev. 1 - 2
1 of 13
www.diodes.com
April 2015
© Diodes Incorporated