AL9901
UNIVERSAL HIGH VOLTAGE LED DRIVER
Description Pin Assignments
The AL9901, high-voltage PWM LED driver provides an efficient
solution for offline, high-brightness LED lamps for rectified line
voltages ranging from 85V up to 305V . The AL9901 has an
AC AC
internal MOSFET that allows switching frequencies up to 300kHz,
with the switching frequency determined by an external single
resistor. The AL9901 topology creates a constant current through the
LEDs providing constant light output. The output current is
programmed by one external resistor.
The LED brightness can be varied by both Linear and PWM dimming,
using the AL9901s LD and PWM pins respectively. The PWM input
U-DFN6040-12
operates with a duty ratio of 0-100% and a frequency of up to several
kHz.
The AL9901 is available in the thermally enhanced U-DFN6040-12
and SO-16 packages. The SO-16 is compliant to high voltage spacing
rules for 230VAC mains applications.
Features
>90% Efficiency
Universal Rectified 85 to 305V Input Range
AC
Internal MOSFET Up to 650V, 2A
High Switching Frequency Up to 300kHz
SO-16
Internal Voltage Regulator Removes Start-Up Resistor
7.5V Regulated Output
Tighter Current Sense Tolerance Better Than 5%
LED Brightness Control with Linear and PWM Dimming
Applications
Internal Over-Temperature Protection (OTP)
LED Offline Lamps
U-DFN6040-12 and SO-16 Packages
High Voltage DC-DC LED Driver
Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
Signage and Decorative LED Lighting
Halogen and Antimony Free. Green Device (Note 3)
Back Lighting of Flat Panel Displays
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
AL9901
Pin Descriptions
Pin Name U-DFN5040-10 SO-16 Functions
Gate 1 14 Gate of Internal MOSFET switch.
NC 2 1, 2, 4, 10,16 No connection
PWM 3 5 Low Frequency PWM Dimming pin, also Enable input. Internal 200k pull-down to GND
Internally regulated supply voltage, 7.5V nominal.
V 4 Can supply up to 1 mA for external circuitry. A sufficient storage capacitor is used to provide
DD
storage when the rectified AC input is near the zero crossing.
6
Linear Dimming input. Changes the current limit threshold at current sense comparator and
LD 5
changes the average LED current.
7
Oscillator control.
A resistor connected between this pin and ground puts the AL9901 into fixed frequency mode and
8
6
R
OSC
sets the switching frequency. A resistor connected between this pin and Gate pin puts the AL9901
into fixed off-time mode and determines the off-time.
7 9 Input voltage
V
IN
CS 8 11 Senses LED string and internal MOSFET switch current
GND 9 12 Device ground
13
Gate driver output. Connect a resistor between this pin and R pin to put the AL9901 into fixed
OSC
DRV 10
off time mode.
SO 11 15 Source of the internal MOSFET Switch
SW 12 3 Drain of the internal MOSFET switch.
EP1 EP1 NA Exposed Pad 1(bottom). Drain connection of internal power MOSFET.
NA Exposed Pad 2 (bottom). Substrate connection of control IC. Connect to GND directly underneath
EP2 EP2
the package and large PCB area to minimise junction to ambient thermal impedance.
Functional Block Diagram
2 of 20
March 2015
AL9901
Diodes Incorporated
www.diodes.com
Document number: DS37713 Rev. 1 - 2