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Diodes |
AL8812
BOOST/BUCK DC-DC CONVERTER FOR DIMMABLE MR16 LED LAMPS
Description
The AL8812 is a monolithic control circuit containing the primary
functions required for DC-to-DC converters with MOSFET in one
package. These devices consist of an internal temperature
compensated reference, comparator, controlled duty cycle oscillator
with an active current limit circuit, driver and high current output
switch. Additionally a 60V, 3.6A MOSFET is integrated for reduced
BOM cost and size. This series is specifically designed for buck and
boost applications with a minimum number of external components.
Pin Assignments
NC 1
GATE 2
INPUT 3
VCC 4
SENSE 5
DRIVE 6
12 DRAIN
11 SOURCE
10 TIMING
9 GND
8 SW/E
7 SW/C
U-DFN6040-12
Features
• Operation from 3.0V to 20V Input
• Integrated 60V, 3.6A MOSFET
• Low Standby Current
• Current Limiting
• Output Voltage Adjustable
• Frequency Operation to 100 kHz
• Precision 2% Reference
• Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
• Halogen and Antimony Free. “Green” Device (Note 3)
Applications
• Low Voltage LED Lighting such as MR-16
• General Purpose DC-DC Converter
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
Dimmable MR-16 LED Driver System Diagram
(For detailed schematic please contact your Diodes Sales Representative)
AL8812
Document number: DS37099 Rev. 1 - 2
1 of 11
www.diodes.com
March 2014
© Diodes Incorporated
Pin Descriptions
Pin
Name
NC
GATE
INPUT
VCC
SENSE
Pin
Number
(U-DFN6040-12)
1
2
3
4
5
DRIVE
6
SW/C
SW/E
GND
TIMING
SOURCE
DRAIN
Exposed PAD1
Exposed PAD2
7
8
9
10
11
12
Function
No Connection
Gate connection of internal MOSFET.
Feedback pin for inverting input of internal comparator
Supply voltage pin
No Connection.
Current drive collector:
Normally connected to VCC directly or via a resistor.
Internal switch transistor collector
Internal switch transistor emitter
Ground Connection
Timing Capacitor to control the switching frequency.
Source connecton of internal MOSFET
Drain connection of internal MOSFET
Exposed Pad of MOSFET Drain
Exposed Pad of AL8812 and connect to PCB ground
Functional Diagram
6
DRIVE
7
SW/C
5
SENSE
VCC
4
INPUT 3
GATE
2
SQ
Q2
R
100
Q1
8
Ipk
Oscillator
CT
SW/E
Comparator
+
_
10
1.25V
Reference
Regulator
TIMING
9
GND
12
DRAIN
11
SOURCE
AL8812
Document number: DS37099 Rev. 1 - 2
2 of 11
www.diodes.com
AL8812
March 2014
© Diodes Incorporated
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