Diodes AL9910S-13 Universal high voltage high brightness led driver Datasheet

AL9910/AL9910A/AL9910-5
UNIVERSAL HIGH VOLTAGE HIGH BRIGHTNESS LED DRIVER
NEW PRODUCT
Description
Pin Assignments
The AL9910/A high voltage PWM LED driver-controller
provides an efficient solution for offline high brightness LED
lamps from rectified line voltages ranging from 85VAC up to
277VAC. The AL9910 drives external MOSFETs at switching
frequencies up to 300kHz, with the switching frequency
determined by a single resistor. The AL9910 topology creates
a constant current through the LEDs providing constant light
output. The output current is programmed by one external
resistor and is ultimately determined by the external
MOSFET chosen and therefore allows many low current
LEDs to be driven as well as a few high current LEDs
The LED brightness can be varied by both Linear and PWM
dimming using the AL9910’s LD and PWM_D pins
respectively. The PWM_D input operates with duty ratio of
0-100% and frequency of up to several kHz.
The AL9910 can withstand input voltages up to 500V which
makes it very resilient to transients at standard mains
voltages. As well as standard SO-8 package the AL9910 is
available in the thermally enhanced SO-8EP package.
(Top View)
8 ROSC
VIN 1
CS 2
AL9910
7 LD
6 VDD
5 PWM_D
GND 3
GATE 4
SO-8
(Top View)
8 ROSC
VIN 1
CS 2
AL9910
7 LD
6 VDD
5 PWM_D
GND 3
GATE 4
SO-8EP
Features
•
•
•
•
•
•
•
•
•
>90% Efficiency
Universal rectified 85 to 277VAC input range
Input voltage up to 500V
Internal voltage regulator removes start-up resistor
o 7.5V MOSFET drive – AL9910
o 10V MOSFET drive – AL9910A
Tighter current sense tolerance: 5% AL9910-5
Drives LED Lamps with both high and low current LEDs
LED brightness control with Linear and PWM dimming
Internal Thermal Protection (OTP)
SO-8 and SO-8EP in “Green” Molding Compound
(No Br, Sb) with Lead Free Finish/ RoHS Compliant (Note 1)
Notes:
Applications
•
•
•
•
•
LED offline lamps
High voltage DC-DC LED Driver
Signage and Decorative LED Lighting
Back Lighting of Flat Panel Displays
General purpose constant current source
1. EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2). All applicable RoHS exemptions applied. Please visit our website at
http://www.diodes.com/products/lead_free.html.
Typical Application Circuit
D1
VAC IN
VDD
C1
BR1
VIN
L1
Q1
AL9910/A
LD
C3
GATE
C2
PWM_D
ROSC
GND
CS
RSENSE
ROSC
AL9910/AL9910A/AL9910-5
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AL99
910/AL
L9910A
A/AL99
910-5
UNIVERSAL HIGH VOL
LTAGE HIGH BRIGHTN
NESS LED DRIVER
NEW PRODUCT
Pin Descriiptions
Pin Name
SO-8
SO-8
8EP
Descriptions
s
VIN
1
1
Input volttage
CS
2
2
Senses LED
L
string and external MOS
SFET switch current
GND
3
3
Device ground
g
Gate
4
4
Drives th
he gate of the external
e
MOSFET switch.
PWM_D
5
5
Low Freq
quency PWM Dimming
D
pin, also Enable inpu
ut. Internal 200
0kΩ pull-down to
t GND
VDD
6
6
pply voltage.
Internallyy regulated sup
•
7.5V nominal for
f AL9910 and
d AL9910-5
10V nominal fo
or AL9910A.
•
ply up to 1 mA for external cirrcuitry. A sufficcient storage ca
apacitor is used
d to
Can supp
provide storage
s
when the rectified AC
C input is near the
t zero crossing.
LD
7
7
Linear Dimming input. Changes
C
the current limit thre
eshold at current sense comp
parator
and chan
nges the average LED curren
nt.
ROSC
8
8
Oscillator control. A ressistor connecte
ed between thiss pin and groun
nd sets the PW
WM
frequenccy. The devicess can be switch
hed into constant off time (PFM) mode by co
onnecting
the exterrnal oscillator re
esistor between ROSC pin and
d the gate of th
he external MO
OSFET.
EP PAD
N/A
EP
Exposed
d Pad (bottom). Connect to GND
G
directly un
nderneath the package.
p
Functiona
al Block Dia
agram
AL9910/AL99
910A/AL9910
0-5
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AL9910/AL9910A/AL9910-5
UNIVERSAL HIGH VOLTAGE HIGH BRIGHTNESS LED DRIVER
Absolute Maximum Ratings (Note 2)
Symbol
Ratings
Unit
Maximum input voltage, VIN, to GND
-0.5 to +520
V
VCS
Maximum CS input pin voltage relative to GND
-0.3 to +0.45
V
VLD
Maximum LD input pin voltage relative to GND
-0.3 to (VDD +0.3)
V
Maximum PWM_D input pin voltage relative to GND
-0.3 to (VDD +0.3)
V
Maximum GATE pin voltage relative to GND
-0.3 to (VDD +0.3)
V
12
V
SO-8 (derate 6.3mW/°C above +25°C)
630
mW
SO-8EP (derate at 22mW/°C above 25°C)
2200
mW
TJ
Junction Temperature Range
+150
°C
TST
Storage Temperature Range
-65 to +150
°C
VIN(MAX)
VPWM_D
VGATE
NEW PRODUCT
VDD(MAX)
Parameter
Maximum VDD pin voltage relative to GND
Continuous Power Dissipation (TA = 25°C)
ESD HBM
Human Body Model ESD Protection (Note 3)
1500
V
ESD MM
Machine Model ESD Protection (Note 3)
300
V
Notes:
2. Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional
operation of the device at these or any other conditions above those listed in the operational sections of this specification is not implied. Exposure
to absolute maximum rating conditions for extended periods may affect device reliability.
all voltages are with respect to Ground. Currents are positive into, negative out of the specified terminal.
3. Semiconductor devices are ESD sensitive and may be damaged by exposure to ESD events. Suitable ESD precautions should be taken when
handling and transporting these devices
Recommended Operating Conditions
Symbol
VINDC
TA
VDD
Parameter
Input DC supply voltage range
Ambient temperature range (Note 4)
Maximum recommended voltage applied to VDD pin (Note 5)
Min
Max
AL9910
AL9910-5
15.0
500
AL9910A
20.0
500
AL9910_S
-40
+85
AL9910_SP
-40
+105
AL9910
AL9910-5
10
AL9910A
11
VEN(LO) Pin PWM_D input low voltage
0
1
VEN(HI) Pin PWM_D input high voltage
2.4
VDD
Notes:
Unit
V
°C
V
V
4. Maximum ambient temperature range is limited by allowable power dissipation. The Exposed pad SO-8EP with its lower thermal impedance allows
the variants using this package to extend the allowable maximum ambient temperature range.
5. When using the AL9910 in isolated LED lamps an auxiliary winding might be used.
AL9910/AL9910A/AL9910-5
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AL9910/AL9910A/AL9910-5
UNIVERSAL HIGH VOLTAGE HIGH BRIGHTNESS LED DRIVER
Electrical Characteristics
(Over recommended operating conditions unless otherwise specified - TA = 25°C)
Specifications apply to AL9910, AL9910A and AL9910-5 unless otherwise specified
Symbol
Parameter
Conditions
IINSD
Shut-down mode supply current
NEW PRODUCT
VDD
Internally regulated voltage
VDD current available for external
circuitry
IDD(ext)
VDD under voltage lockout
threshold
UVLO
Pin PWM_D to GND,
VIN = VIN(MIN) (Note 6)
Typ.
Max
AL9910
AL9910-5
0.50
1
AL9910A
0.65
1.2
7.0
7.5
8.0
9.5
10
10.5
AL9910
VIN = VIN(MIN)~500V, (Note 6)
AL9910-5
lDD(ext) = 0, Gate pin open
AL9910A
Min
VIN = VIN(Min) to 100V (Notes 6 & 7)
VDD rising
VDD under voltage lockout
∆UVLO hysteresis
VDD falling
RPWM_D PWM_D pull-down resistance
VPWM_D = 5V
VCS(HI)
Full ambient temperature
range (Note 8)
1.0
AL9910
AL9910-5
6.4
6.7
7
AL9910A
8.4
9
9.6
AL9910
AL9910-5
500
AL9910A
Current sense threshold voltage
AL9910
AL9910A
AL9910-5
Unit
mA
V
mA
V
mV
750
150
200
250
225
250
275
237.5
250
262.5
kΩ
mV
VGATE(HI) GATE high output voltage
IOUT = 10mA
VDD -0.3
VDD
V
VGATE(LO) GATE low output voltage
IOUT = -10mA
0
0.3
V
ROSC = 1MΩ
20
25
30
ROSC = 226kΩ
80
100
120
fOSC
Oscillator frequency
Maximum Oscillator PWM Duty
Cycle
fPWMhf = 25kHz, at GATE,
CS to GND.
Linear Dimming pin voltage range
Full ambient temperature range (Note 8),
VIN = 20V
tBLANK
Current sense blanking interval
VCS = 0.45V, VLD = VDD
tDELAY
Delay from CS trip to GATE lo
DMAXhf
VLD
kHz
100
%
0
-
250
mV
160
250
440
ns
300
ns
VIN = 20V, VLD = 0.15,
VCS = 0 to 0.22V after TBLANK
tRISE
GATE output rise time
CGATE = 500pF
30
50
ns
tFALL
GATE output fall time
CGATE = 500pF
30
50
ns
TSD
Thermal shut down
150
TSDH
Thermal shut down hysteresis
50
θJA
Thermal Resistance Junction-toAmbient
θJC
Thermal Resistance Junction-toCase
Notes:
SO-8 (Note 9)
110
SO-8EP (Note 10)
66
SO-8 (Note 9)
22
SO-8EP (Note 10)
9
°C
°C/W
°C/W
6. VIN(MIN) for the AL9910 is 15V and for the AL9910A it is 20V.
7. Also limited by package power dissipation limit, whichever is lower.
8. Full ambient temperature range for AL9910-5S, AL9910AS and AL9910S is -40 to +85°C; for AL9910-5SP, AL9910ASP and AL9910SP is
-40 to +105°C.
9. Device mounted on FR-4 PCB (25mm x 25mm 1oz copper, minimum recommended pad layout on top. For better thermal performance, larger
copper pad for heat-sink is needed.
10. Device mounted on FR-4 PCB (51mm x 51mm 2oz copper, minimum recommended pad layout on top layer and thermal vias to bottom layer
ground plane. For better thermal performance, larger copper pad for heat-sink is needed.
AL9910/AL9910A/AL9910-5
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AL9910/AL9910A/AL9910-5
UNIVERSAL HIGH VOLTAGE HIGH BRIGHTNESS LED DRIVER
460
2.5
440
2.0
420
INPUT CURRENT (µA)
CURRENT SENSE THRESHOLD (mV)
3.0
1.5
1.0
0.5
0.0
V IN = 400V
400
V IN = 15V
380
360
340
-0.5
320
-1.0
300
-1.5
-40
280
-40
-15
10
35
60
85
AMBIENT TEMPERATURE (°C)
Change in Current Sense Threshold vs. Ambient Temperature
85
SHORT CIR CUIT OU TPUT CURRENT (mA)
450
1.0
CHANGE IN FREQUENCY (%)
-15
10
35
60
AMBIENT TEMPERATURE (° C)
Input Current vs. Ambient Temperature
1.5
0.5
R OSC = 226kΩ
0.0
-0.5
ROSC = 1M Ω
-1.0
-1.5
-2.0
-40
-15
10
35
60
85
AMBIENT TEMPERATURE (°C)
Change in Oscillation Frequency vs. Ambient Temperature
ILED(NOM) = 180mA
400
350
300
250
200
150
85 105 125 145 165 185 205 225 245 265
INPUT VOLTAGE (VRMS )
180mA LED Driver Short Circuit Output Current vs. Input Voltage
100
ILED = 281mA
90
V IN = 264V
TA = 23.5C
80
70
IO UT MAX (%)
NEW PRODUCT
Typical Characteristics
60
50
40
30
20
10
0
0
50
100
150
200
250
V LD DIMMING CONTROL (mV)
I OUT MAX vs. V LD Dimming Control
AL9910/AL9910A/AL9910-5
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300
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AL9910/AL9910A/AL9910-5
UNIVERSAL HIGH VOLTAGE HIGH BRIGHTNESS LED DRIVER
Typical Characteristics (cont.) Measured using AL9910EV4
200
95
15 LEDs
14 LEDs
190
18 LEDs
EFFICIENCY (%)
IOUT MAX (mA)
16 LEDs
170
17 LEDs
160
90
17 LEDs
14 LEDs
16 LEDs
85
15 LEDs
150
18 LEDs
140
85
80
85
105 125 145 165 185 205 225 245 265
INPUT VOLTAGE (VRMS )
180mA LED Driver Output Current vs. Input Voltage
105 125 145 165 185 205 225 245 265
INPUT VOLTAGE (VRMS )
180mA LED Driver Efficiency vs. Input Voltage
12
0.95
17 LEDs
18 LEDs
18 LEDs
0.9
POWER (W)
10
POWER FACTOR
NEW PRODUCT
180
16 LEDs
0.85
17 LEDs
0.8
16 LEDs
8
15 LEDs
14 LEDs
15 LEDs
6
0.75
14 LEDs
0.7
85
105 125 145 165 185 205 225 245 265
INPUT VOLTAGE (VRMS )
180mA LED Driver Power Factor vs. Input Voltage
AL9910/AL9910A/AL9910-5
Document number: DS35103 Rev. 7 - 2
4
85
105 125 145 165 185 205 225 245 265
INPUT VOLTAGE (VRMS )
180mA LED Driver Input Power Dissipation vs. Input Voltage
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AL9910/AL9910A/AL9910-5
UNIVERSAL HIGH VOLTAGE HIGH BRIGHTNESS LED DRIVER
Applications Information
The AL9910 is very versatile and is capable of operating in isolated or non-isolated topologies. It can also be made to operate
in continuous as well as discontinuous conduction mode.
VIN
VIN
7.5/10V
LDO
OSC
VDD
VDD
NEW PRODUCT
ROSC
250mV
S
R
LD
O
GATE
CS
OTP
PWM_D
100k
AL9910/AL9910A
RSENSE
GND
Fig. 1 Functional Block Diagram
The AL9910 contains a high voltage LDO (see figure 1) the output of the LDO provides a power rail to the internal circuitry
including the gate driver. A UVLO on the output of the LDO prevents incorrect operation at low input voltage to the VIN pin.
In a non-isolated Buck LED driver when the gate pin goes high the external power MOSFET Q1 is turned on causing current
to flow through the LEDs, inductor (L1) and current sense resistor (RSENSE). When the voltage across RSENSE exceeds the
current sense pin threshold the external MOSFET Q1 is turned off. The stored energy in the inductor causes the current to
continue to flow through the LEDs via diode D1.
The AL9910’s LDO provides all power to the rest of the IC including Gate drive this removes the need for large high power
start-up resistors. This means that operate correctly it requires around 0.5mA from the high voltage power rail. The LDO can
also be used to supply up to 1mA to external circuits.
The AL9910 operates and regulates by limiting the peak current of the external MOSFET; the peak current sense threshold is
nominally set at 250mV.
The same basic operation is true for isolated topologies, however in these the energy stored in the transformer delivers
energy to LEDs during the off-cycle of the external MOSFET.
Design Parameters
Setting the LED Current
In the non-isolated buck converter topology, figure 1, the average LED current is not the peak current divided by 2 - however,
there is a certain error due to the difference between the peak and the average current in the inductor. The following equation
accounts for this error:
250mV
R SENSE =
.
(ILED + (0.5 * IRIPPLE )))
AL9910/AL9910A/AL9910-5
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AL9910/AL9910A/AL9910-5
UNIVERSAL HIGH VOLTAGE HIGH BRIGHTNESS LED DRIVER
Applications Information (cont.)
Setting Operating Frequency
NEW PRODUCT
The AL9910 is capable of operating over a 25 and 300 kHz switching frequency range. The switching frequency is
programmed by connecting an external resistor between ROSC pin and ground. The corresponding oscillator period is:
+ 22
R
µs
with ROSC in kΩ
tOSC = osc
25
The switching frequency is the reciprocal of the oscillator period. Typical values for ROSC vary from 75kΩ to 1MΩ
When driving smaller numbers of LEDs, care should be taken to ensure that tON > tBLANK. The simplest way to do this is to
reduce/limit the switching frequency by increasing the ROSC value. Reducing the switching frequency will also improve the
efficiency.
When operating in buck mode the designer must keep in mind that the input voltage must be maintained higher than 2 times
the forward voltage drop across the LEDs. This limitation is related to the output current instability that may develop when the
AL9910 operates at a duty cycle greater than 0.5. This instability reveals itself as an oscillation of the output current at a subharmonic (SBO) of the switching frequency.
The best solution is to adopt the so-called constant off-time operation as shown in Figure 2. The resistor (ROSC) is, connected
to ground by default, to set operating frequency. To force the AL9910 to enter constant OFF time mode ROSC is connected to
the gate of the external MOSFET. This will decrease the duty cycle from 50% by increasing the total period, tOFF + tON.
VIN
VDD
LD
VIN
Q1
AL9910/A GATE
CS
PWM_D
ROSC
GND
ROSC
Fig. 2 Constant Off-Time Configuration
The oscillator period equation above now defines the AL9910 off time, tOFF.
When using this mode the nominal switching frequency is chosen and from the nominal input and output voltages the off-time
can be calculated:
⎛
VOUT(nom ) ⎞
⎟∗ 1
t OFF = ⎜1 −
⎜
VIN(nom ) ⎟⎠ fOSC
⎝
From this the timing resistor, ROSC, can be calculated: R OSC = (t OFF (µs) ∗ 25 ) − 22(kΩ)
AL9910/AL9910A/AL9910-5
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AL9910/AL9910A/AL9910-5
UNIVERSAL HIGH VOLTAGE HIGH BRIGHTNESS LED DRIVER
Applications Information (cont.)
Inductor Selection
NEW PRODUCT
The non-isolated buck circuit, Figure 1, is usually selected and it has two operation modes: continuous and discontinuous
conduction modes. A buck power stage can be designed to operate in continuous mode for load current above a certain level
usually 15% to 30% of full load. Usually, the input voltage range, the output voltage and load current are defined by the power
stage specification. This leaves the inductor value as the only design parameter to maintain continuous conduction mode.
The minimum value of inductor to maintain continuous conduction mode can be determined by the following example.
The required inductor value is determined from the desired peak-to-peak LED ripple current in the inductor; typically around
30% of the nominal LED current.
(VIN − VLEDs ) × D
Where D is duty cycle
L=
(0.3 × ILED ) × fOSC
The next step is determining the total voltage drop across the LED string. For example, when the string consists of
10 High-Brightness LEDs and each diode has a forward voltage drop of 3.0V at its nominal current; the total LED voltage
VLEDS is 30V.
Dimming
The LED brightness can be dimmed either linearly (using the LD pin) or via pulse width modulation (using the PWM-D pin); or
a combination of both - depending on the application. Pulling the PWM_D pin to ground will turn off the AL9910. When
disabled, the AL9910’s quiescent current is typically 0.5mA (0.65 for AL9910A). Reducing the LD voltage will reduce the LED
current but it will not entirely turn off the external power transistor and hence the LED current – this is due to the finite
blanking period. Only the PWM_D pin will turn off the power transistor.
Linear dimming is accomplished by applying a 45 to 250mV analog signal to the LD pin. This overrides the default 250mV
threshold level of the CS pin and reduces the output current. If an input voltage greater than 250mV is applied to the LD then
the output current will not change.
The LD pin also provides a simple cost effective solution to soft start; by connecting a capacitor to the LD pin down to ground
at initial power up the LD pin will be held low causing the sense threshold to be low. As the capacitor charges up the current
sense threshold will increase thereby causing the average LED current to increase.
PWM dimming is achieved by applying an external PWM signal to the PWM_D pin. The LED current is proportional to the
PWM duty cycle and the light output can be adjusted between zero and 100%.. The PWM signal enables and disables the
AL9910 - modulating the LED current. The ultimate accuracy of the PWM dimming method is limited only by the minimum
gate pulse width, which is a fraction of a percentage of the low frequency duty cycle. PWM dimming of the LED light can be
achieved by turning on and off the converter with low frequency 50Hz to 1000Hz TTL logic level signal.
With both modes of dimming it is not possible to achieve average brightness levels higher than the one set by the current
sense threshold level of the AL9910. If a greater LED current is required then a smaller sense resistor should be used
Output Open Circuit Protection
The non-isolated buck LED driver topology provides inherent protection against an open circuit condition in the LED string
due to the LEDs being connected in series with the inductor. Should the LED string become open circuit then no switching
occurs and the circuit can be permanently left in this state with damage to the rest of the circuit.
AL9910/AL9910A/AL9910-5
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AL9910/AL9910A/AL9910-5
UNIVERSAL HIGH VOLTAGE HIGH BRIGHTNESS LED DRIVER
Applications Information (cont.)
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.
LED +
NEW PRODUCT
D1
VAC IN
VDD
C1
C2
BR1
LD
VIN
C3
L1
LED -
AL9910/A
PWM_D
ROSC
GND
Q1
GATE
CS
RSENSE
ROSC
Fig. 3 Typical Application Circuit (without PFC)
Buck Design Equations:
D=
VLEDs
VIN
t ON =
L≥
D
fosc
( VIN − VLEDs ) × t ON
0.3 × ILED
R SENSE =
0.25
where ILED x 0.3 = IRIPPLE
ILED + (0.5 × (ILED × 0.3))
Design Example
For an AC line voltage of 120V the nominal rectified input voltage VIN = 120V*1.41 = 169V. From this and the LED chain
voltage the duty cycle can be determined:
D = VLEDs /VIN = 30/169 = 0.177
From the switching frequency, for example fOSC = 50kHz, the required on-time of the external MOSFET can be calculated:
tON = D/fOSC = 3.5 µs
The value of the inductor for an LED current of 350mA is determined as follows:
L = (VIN - VLEDs) * tON /(0.3 * ILED) = 4.6mH
AL9910/AL9910A/AL9910-5
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AL9910/AL9910A/AL9910-5
UNIVERSAL HIGH VOLTAGE HIGH BRIGHTNESS LED DRIVER
Applications Information (cont.)
Input Bulk Capacitor
For Offline lamps an input bulk capacitor is required to ensure that the rectified AC voltage is held above twice the LED string
voltage throughout the AC line cycle. The value can be calculated from:
CIN ≥
PIN × (1 − D CH )
2 × VLINE _ MIN × 2fL × ΔVDC _ MAX
NEW PRODUCT
Where
Dch : Capacity charge work period, generally about 0.2~0.25
fL : Input frequency for full range (85~265VRMS)
ΔVDC _ MAX Should be set 10~15% of
2 VLINE _ MIN
If the capacitor has a 15% voltage ripple then a simplified formula for the minimum value of the bulk input capacitor
approximates to:
I
× VLEDs × 0.06
CMIN = LED
VIN2
Power Factor Correction
If power factor improvement is required then for the input power less than 25W, a simple passive power factor correction
circuit can be added to the AL9910 typical application circuit. Figure 4 shows that passive PFC circuitry (3 current steering
diodes and 2 identical capacitors) does not significantly affect the rest of the circuit. Simple passive PFC improves the line
current harmonic distortion and achieves a power factor greater than 0.85.
Passive PFC
LED +
C4
C1
D1
VAC IN
VDD
BR1
LD
C2
C3
VIN
AL9910/A
PWM_D
ROSC
GND
Q1
LED L1
GATE
CS
RSENSE
ROSC
Fig. 4 Typical Application Circuit with Passive PFC
Each of these identical capacitors should be rated for half of the input voltage and have twice as much capacitance as the
calculated CMIN of the buck converter circuit without passive PFC (see above section on bulk capacitor calculation).
For further design information please see AN75 from the Diodes website.
AL9910/AL9910A/AL9910-5
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February 2012
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AL9910/AL9910A/AL9910-5
UNIVERSAL HIGH VOLTAGE HIGH BRIGHTNESS LED DRIVER
Applications Information (cont.)
DC-DC Buck LED Driver
The design procedure for an ac input buck LED driver outlined in the previous chapters equally applies DC input LED drivers.
When driving long LED chains care should be taken not to induce SBO – maximum LED chain voltage should be less half of
VIN. So either maximum duty cycle should be kept below 50% or use of constant off-time removes this issue.
NEW PRODUCT
DC-DC Boost LED Driver
Due to the topology of the AL9910 LED driver-controller it is capable of being used in boost configurations – at reduced
accuracy. The accuracy can be improved by measuring the LED current with an op amp and use the op amp’s output to drive
the LD pin.
A Boost LED driver is used when the forward voltage drop of the LED string is higher than the input supply voltage. For
example, the Boost topology can be appropriate when input voltage is supplied by a 48V power supply and the LED string
consists of twenty HB LEDs, as the case may be for a street light.
L1
VDD
C1
VIN
VIN
D1
Q1
AL9910/A
PWM_D
GATE
C2
LD
ROSC
CS
C3
GND
ROSC
RSENSE
Fig. 5 Boost LED Driver
In a Boost converter, when the external MOSFET is ON the energy is stored in the inductor which is then delivered to the
output when the external MOSFET switches OFF. If the energy stored in the inductor is not fully depleted by the next
switching cycle (continuous conduction mode) the DC conversion between input and output voltage is given by:
V
− VIN
V
VOUT = IN Î D = OUT
VOUT
1− D
From the switching frequency, fOSC, the on-time of the MOSFET can be calculated:
D
t ON =
fOSC
From this the required inductor value can be determined by:
V ∗t
L = IN ON
0.3 ∗ ILED
The Boost topology LED driver requires an output capacitor to deliver current to the LED string during the time that the
external MOSFET is on.
In boost LED driver topologies if the LEDs should become open circuit damage may occur to the power switch and so some
form of detection should be present to provide Over-voltage detection/protection.
AL9910/AL9910A/AL9910-5
Document number: DS35103 Rev. 7 - 2
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February 2012
© Diodes Incorporated
AL99
910/AL
L9910A
A/AL99
910-5
UNIVERSAL HIGH VOL
LTAGE HIGH BRIGHTN
NESS LED DRIVER
Ordering Information
n
AL
L9910 X XX XX - 13
Varia
ant
NEW PRODUCT
Blank : 7.5V VDD
A : 10V
1
VDD
Device
AL9910-5S-13
3
AL9910-5SP-1
13
AL9910AS-13
AL9910ASP-13
AL9910S-13
AL9910SP-13
Notes:
VCS Tolerancce
Blank : 10%
%
-5 : 5%
Pa
ackage
Packing
S : SO-8
SP : SO-8EP
VCS Tolerrance
Pac
ckage
Code
Packaging
(Note 10)
±5%
%
±5%
%
±10%
%
±10%
%
±10%
%
±10%
%
S
SP
S
S
S
SP
S
S
SP
SO-8
SO-8EP
SO-8
SO-8EP
SO-8
SO-8EP
pe & Reel
13 : 13” Tap
13” Tape and Reel
Qua
antity
Part Numberr Suffix
2500/Tap
pe & Reel
2500/Tap
pe & Reel
2500/Tap
pe & Reel
2500/Tap
pe & Reel
2500/Tap
pe & Reel
2500/Tap
pe & Reel
-13
-13
-13
-13
-13
-13
10. Pad
d layout as shown on Diodes Inc. sug
ggested pad layout document AP0200
01, which can be fo
ound on our website
e at
http
p://www.diodes.com
m/datasheets/ap02
2001.pdf .
Marking In
nformation
n
(1) SO-8
(2) SO-8EP
AL9910/AL99
910A/AL9910
0-5
Document numberr: DS35103 Rev. 7 - 2
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ww.diodes.com
Febru
uary 2012
© Diodes Incorporated
AL9910/AL9910A/AL9910-5
UNIVERSAL HIGH VOLTAGE HIGH BRIGHTNESS LED DRIVER
Package Outline Dimensions (All Dimensions in mm)
0.254
(1) Package Type: SO-8
E1 E
Gauge Plane
Seating Plane
A1
NEW PRODUCT
L
Detail ‘A’
7°~9°
h
45°
Detail ‘A’
A2 A A3
b
e
D
SO-8
Dim
Min
Max
A
1.75
A1
0.10
0.20
A2
1.30
1.50
A3
0.15
0.25
b
0.3
0.5
D
4.85
4.95
E
5.90
6.10
E1
3.85
3.95
e
1.27 Typ
h
0.35
L
0.62
0.82
0°
8°
θ
All Dimensions in mm
(2) Package Type: SO-8EP
Exposed Pad
8
5
E1
1
H
4
F
b
Bottom View
E
9° (All sides)
N
7°
A
e
D
A1
AL9910/AL9910A/AL9910-5
Document number: DS35103 Rev. 7 - 2
45°
Q
C
4° ± 3°
Gauge Plane
Seating Plane
E0
L
14 of 16
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SO-8EP (SOP-8L-EP)
Dim Min Max Typ
A 1.40 1.50 1.45
A1 0.00 0.13
b 0.30 0.50 0.40
C 0.15 0.25 0.20
D 4.85 4.95 4.90
E 3.80 3.90 3.85
E0 3.85 3.95 3.90
E1 5.90 6.10 6.00
e
1.27
F 2.75 3.35 3.05
H 2.11 2.71 2.41
L 0.62 0.82 0.72
N
0.35
Q 0.60 0.70 0.65
All Dimensions in mm
February 2012
© Diodes Incorporated
AL9910/AL9910A/AL9910-5
UNIVERSAL HIGH VOLTAGE HIGH BRIGHTNESS LED DRIVER
Suggested Pad Layout
(1) Package Type: SO-8
NEW PRODUCT
X
C1
C2
Dimensions
X
Y
C1
C2
Value (in mm)
0.60
1.55
5.4
1.27
Dimensions
X
Y
X1
Y1
C1
C2
Value (in mm)
0.60
1.55
3.30
2.66
5.4
1.27
Y
(2) Package Type: SO-8EP
X
Exposed Pad
X1
C1
Y1
Y
C2
AL9910/AL9910A/AL9910-5
Document number: DS35103 Rev. 7 - 2
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February 2012
© Diodes Incorporated
AL9910/AL9910A/AL9910-5
UNIVERSAL HIGH VOLTAGE HIGH BRIGHTNESS LED DRIVER
IMPORTANT NOTICE
DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS
DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).
NEW PRODUCT
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changes without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability
arising out of the application or use of this document or any product described herein; neither does Diodes Incorporated convey any
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herein in such applications shall assume all risks of such use and will agree to hold Diodes Incorporated and all the companies
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Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized
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Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall
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arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.
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LIFE SUPPORT
Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without
the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body, or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided
in the labeling can be reasonably expected to result in significant injury to the user.
B.
A critical component is any component in a life support device or system whose failure to perform can be reasonably expected
to cause the failure of the life support device or to affect its safety or effectiveness.
Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or
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concerning their products and any use of Diodes Incorporated products in such safety-critical, life support devices or systems,
notwithstanding any devices- or systems-related information or support that may be provided by Diodes Incorporated. Further,
Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes
Incorporated products in such safety-critical, life support devices or systems.
Copyright © 2012, Diodes Incorporated
www.diodes.com
AL9910/AL9910A/AL9910-5
Document number: DS35103 Rev. 7 - 2
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February 2012
© Diodes Incorporated
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