Diodes AL9910/ AL9910A/ AL9910-5/ AL9910A-5 - Manual (Page 2)

AL9910/ AL9910A/ AL9910-5/ AL9910-5A
Document number: DS35103 Rev. 9 - 2
2 of 15
www.diodes.com
May 2014
© Diodes Incorporated
AL9910/ AL9910A/ AL9910-5/ AL9910A-5
Typical Applications Circuit
Pin Descriptions
Pin
Name
Pin Number
Function
SO-8 SO-8EP
V
IN
1 1 Input Voltage
CS 2 2 Senses LED string and external MOSFET switch current
GND 3 3 Device Ground
Gate 4 4 Drives the gate of the external MOSFET switch.
PWM_D 5 5 Low Frequency PWM Dimming pin, also Enable input. Internal 200kΩ pull-down to GND.
V
DD
6 6
Internally regulated supply voltage.
ƒ 7.5V nominal for AL9910 and AL9910-5
ƒ 10V nominal for AL9910A.
Can supply up to 1 mA for external circuitry. A sufficient storage capacitor is used to provide storage when
the rectified AC input is near the zero crossing.
LD 7 7
Linear Dimming Input. Changes the current limit threshold at current sense comparator and changes the
average LED current.
R
OSC
8 8
Oscillator Control. A resistor connected between this pin and ground sets the PWM frequency. The devices
can be switched into constant off time (PFM) mode by connecting the external oscillator resistor between
R
OSC
pin and the gate of the external MOSFET.
EP PAD N/A EP Exposed Pad (bottom). Connect to GND directly underneath the package.
Functional Block Diagram
R
SENSE
AL9910/A
GATE
CS
LD
PWM_D
GND R
OSC
V
DD
V
IN
V
AC
IN
Q1
L1
D1
C1
R
OSC
C2
C3
BR1
R
SENSE
AL9910/A
GATE
CS
LD
PWM_D
GND R
OSC
V
DD
V
IN
V
AC
IN
Q1
L1
D1
C1
R
OSC
C2
C3
BR1