AL9910AS-13 Diodes Zetex, AL9910AS-13 Datasheet - Page 9

• Manufacturer Part Number: AL9910AS-13
• Manufacturer: Diodes Zetex

Specifications of AL9910AS-13

• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Package Type: SO
• Pin Count: 8
• Mounting: Surface Mount
• Operating Supply Voltage (max): 11V
• Lead Free Status / Rohs Status: Compliant

Applications Information
AC/DC Off-Line LED driver
The AL9910 is a cost-effective off-line buck LED driver-controller specifically designed for driving LED strings. It is suitable for
being used with either rectified AC line or any DC voltage between 15-500V. See figure 3 for typical circuit.
Buck design equations:
Design example
For an AC line voltage of 120V the nominal rectified input voltage V
voltage the duty cycle can be determined:
From the switching frequency, for example f
The value of the inductor is determined as follows:
AL9910/AL9910A
Document number: DS 35103 Rev. 2 - 2
V
V
D = V
t
L = (V
D
L
R
t
ON
AC
AC
ON
SENSE
≥
=
IN
IN
= D/f
(
V
=
V
LEDs
IN
LEDs
V
IN
IN
f
OSC
- V
=
osc
D
−
0
/V
3 .
LEDs
V
I
LED
IN
= 3.5 µs
LEDs
×
= 30/169 = 0.177
I
) * t
LED
+
)
0 (
BR1
BR1
ON
×
5 .
t
ON
. 0
/(0.3 * I
×
25
I (
LED
Figure 3. Typical Application Circuit (without PFC)
(Continued)
LED
×
C1
C1
0
) = 4.6mH
3 .
))
OSC
C2
C2
where I
= 50kHz, the required on-time of the external MOSFET can be calculated:
UNIVERSAL HIGH VOLTAGE HIGH BRIGHTNESS LED
LED
www.diodes.com
R
R
x 0.3 = I
OSC
OSC
V
V
LD
LD
PWM_D
PWM_D
DD
DD
R
R
9 of 14
OSC
OSC
AL9910/A
AL9910/A
RIPPLE
GND
GND
V
V
IN
IN
IN
= 120V*1.41 = 169V. From this and the LED chain
GATE
GATE
CS
CS
Q1
Q1
AL9910/AL9910A
R
R
D1
D1
SENSE
SENSE
L1
L1
C3
C3
© Diodes Incorporated
LED +
LED +
LED -
LED -
March 2011
DRIVER