AL9910 Datasheet »

AL9910/ AL9910A/ AL9910-5/ AL9910A-5
UNIVERSAL HIGH VOLTAGE HIGH BRIGHTNESS LED DRIVER
Description
Pin Assignments
(Top View)
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
8 ROSC
VIN 1
CS 2
GND 3
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
AL9910
GATE 4
constant light output. The output current is programmed by one
external resistor and is ultimately determined by the external
7 LD
6 VDD
5 PWM_D
SO-8
MOSFET chosen and therefore allows many low current LEDs to be
driven as well as a few high current LEDs.
(Top View)
The LED brightness can be varied by both Linear and PWM dimming
8 ROSC
VIN 1
using the AL9910’s LD and PWM_D pins respectively. The PWM_D
CS 2
GND 3
GATE 4
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
AL9910
7 LD
6 VDD
5 PWM_D
very resilient to transients at standard mains voltages. As well as
SO-8EP
standard SO-8 package the AL9910 is available in the thermally
enhanced SO-8EP package.
Features
•
•
>90% Efficiency
Universal Rectified 85 to 277VAC Input Range
•
Input Voltage Up to 500V
•
Internal Voltage Regulator Removes Start-Up Resistor
ƒ
7.5V MOSFET Drive – AL9910
ƒ
10V MOSFET Drive – AL9910A
•
Tighter Current Sense Tolerance: 5% AL9910-5, AL9910A-5
•
Drives LED Lamps with Both High and Low Current LEDs
•
LED Brightness Control with Linear and PWM Dimming
•
Internal Thermal Protection (OTP)
•
Available in SO-8 and SO-8EP Packages
•
Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
•
Halogen and Antimony Free. “Green” Device (Note 3) 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. 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.
AL9910/ AL9910A/ AL9910-5/ AL9910-5A
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AL9910/ AL9910A/ AL9910-5/ AL9910A-5
Typical Applications Circuit
VAC IN
VDD
C1
BR1
D1
VIN
C2
PWM_D
ROSC
GND
L1
Q1
AL9910/A
LD
C3
GATE
CS
RSENSE
ROSC
Pin Descriptions
Pin Number
Pin
Name
SO-8
SO-8EP
VIN
1
1
Input Voltage
CS
GND
Gate
2
3
4
2
3
4
Senses LED string and external MOSFET switch current
Device Ground
Drives the gate of the external MOSFET switch.
PWM_D
5
5
VDD
6
6
Low Frequency PWM Dimming pin, also Enable input. Internal 200kΩ pull-down to GND.
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
ROSC
8
8
EP PAD
N/A
EP
Function
Linear Dimming Input. Changes the current limit threshold at current sense comparator and changes the
average LED current.
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
ROSC pin and the gate of the external MOSFET.
Exposed Pad (bottom). Connect to GND directly underneath the package.
Functional Block Diagram
AL9910/ AL9910A/ AL9910-5/ AL9910-5A
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AL9910/ AL9910A/ AL9910-5/ AL9910A-5
Absolute Maximum Ratings (Note 4) (@TA = +25°C, unless otherwise specified.)
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
VIN(MAX)
VPWM_D
VGATE
VDD(MAX)
Parameter
Maximum VDD Pin Voltage Relative to GND
Continuous Power Dissipation (TA = +25°C)
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
1500
300
V
V
ESD HBM
ESD MM
Notes:
Human Body Model ESD Protection (Note 5)
Machine Model ESD Protection (Note 5)
4. 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.
5. 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 (@TA = +25°C, unless otherwise specified.)
Symbol
VINDC
TA
VDD
Parameter
Input DC Supply Voltage Range
Ambient Temperature Range (Note 6)
Maximum Recommended Voltage Applied to VDD Pin (Note 7)
Min
Max
AL9910
AL9910-5
15.0
500
AL9910A
Al9910A-5
20.0
500
-40
-40
+85
+105
AL9910_S
AL9910_SP
AL9910
AL9910-5
V
°C
10
V
AL9910A
AL9910A-5
12
VEN(LO)
Pin PWM_D Input Low Voltage
0
1
VEN(HI)
Pin PWM_D Input High Voltage
2.4
VDD
Notes:
Unit
V
6. 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.
7. When using the AL9910 in isolated LED lamps an auxiliary winding might be used.
AL9910/ AL9910A/ AL9910-5/ AL9910-5A
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AL9910/ AL9910A/ AL9910-5/ AL9910A-5
Electrical Characteristics (@TA = +25°C, unless otherwise specified.)
Symbol
Parameter
Shut-Down Mode Supply Current
IINSD
Internally Regulated Voltage
VDD
Conditions
Pin PWM_D to GND,
VIN = VIN(MIN) (Note 6)
VIN = VIN(MIN) ~500V, (Note 8)
lDD(ext) = 0, Gate pin open
IDD(ext)
VDD Current Available for External
Circuitry
UVLO
VDD Under Voltage Lockout Threshold VDD rising
∆UVLO
RPWM_D
VDD Under Voltage Lockout Hysteresis
PWM_D Pull-Down Resistance
Min
AL9910A
AL9910
AL9910-5
AL9910A
Current Sense Threshold Voltage
Max
0.50
1
0.65
1.2
7.0
7.5
8.0
9
10
11
1.0
VIN = VIN(MIN) to 100V (Notes 8 & 9)
AL9910
AL9910-5
AL9910A
6.4
6.7
7
8
9
10
AL9910
AL9910-5
AL9910A
VDD falling
VPWM_D = 5V
AL9910
VCS(HI)
Typ
AL9910
AL9910-5
Full ambient temperature range
(Note 10)
AL9910A
AL9910A-5
AL9910-5
500
150
200
250
225
250
275
230
255
280
242
255
267
237.5
250
262.5
0.3
V
0
20
25
30
ROSC = 226kΩ
80
100
120
VDD -0.3
DMAXhf
Maximum Oscillator PWM Duty Cycle
fPWMhf = 25kHz, at GATE,
CS to GND.
VLD
Linear Dimming Pin Voltage Range
Full ambient temperature range (Note 10),
VIN = 20V
Current Sense Blanking Interval
VCS = 0.45V, VLD = VDD
Delay From CS Trip to GATE lo
VIN = 20V, VLD = 0.15,
VCS = 0 to 0.22V after TBLANK
tRISE
GATE Output Rise Time
CGATE = 500pF
tFALL
GATE Output Fall Time
CGATE = 500pF
TSD
Thermal Shut Down
150
TSDH
Thermal Shut Down Hysteresis
50
Thermal Resistance Junction-toAmbient
θJC
Thermal Resistance Junction-to-Case
Notes:
kΩ
V
ROSC = 1MΩ
θJA
V
VDD
IOUT = -10mA
tDELAY
mA
mV
VGATE(LO) GATE Low Output Voltage
tBLANK
V
mV
IOUT = 10mA
Oscillator Frequency
mA
750
VGATE(HI) GATE High Output Voltage
fOSC
Unit
kHz
100
%
0
-
250
mV
160
250
440
ns
300
ns
30
50
ns
30
50
ns
SO-8 (Note 11)
SO-8EP (Note 12)
SO-8 (Note 11)
110
66
22
SO-8EP (Note 12)
9
°C
°C/W
°C/W
8. VIN(MIN) for the AL9910 is 15V and for the AL9910A it is 20V.
9. Also limited by package power dissipation limit, whichever is lower.
10. Full ambient temperature range for AL9910-5S, AL9910AS and AL9910S is -40 to +85°C; for AL9910-5SP, AL9910ASP and AL9910SP is
-40°C to +105°C.
11. 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.
12. 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/ AL9910-5A
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AL9910/ AL9910A/ AL9910-5/ AL9910A-5
3.0
460
2.5
440
2.0
420
INPUT CURRENT (µA)
CURRENT SENSE THRESHOLD (mV)
Typical Characteristics
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
Input Current vs. Ambient Temperature
SHORT CIRCUIT OU TPUT CURRENT (mA)
ILED = 281mA
V IN = 264V
TA = 23.5C
80
IOUT MAX (%)
70
60
50
40
30
20
10
0
85
450
100
90
-15
10
35
60
AMBIENT TEMPERATURE (°C)
0
100
150
200
250
V LD DIMMING CONTROL (mV)
I OUT MAX vs. V LD Dimming Control
50
300
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
1.5
CHANGE IN FREQUENCY (%)
1.0
0.5
0.0
ROSC = 226kΩ
-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
AL9910/ AL9910A/ AL9910-5/ AL9910-5A
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Typical Characteristics (cont.) measured using AL9910EV4
200
95
15 LEDs
14 LEDs
190
18 LEDs
EFFICIENCY (%)
IOUT MAX (mA)
180
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
0.85
POWER (W)
POWER FACTOR
10
16 LEDs
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/ AL9910-5A
Document number: DS35103 Rev. 9 - 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/ AL9910A-5
Application 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
250mV
S
R
LD
O
ROSC
GATE
CS
OTP
PWM_D
100k
AL9910/AL9910A
RSENSE
GND
Figure 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:
R SENSE =
(ILED
250mV
.
+ (0.5 * IRIPPLE )))
AL9910/ AL9910A/ AL9910-5/ AL9910-5A
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AL9910/ AL9910A/ AL9910-5/ AL9910A-5
Applications Information (cont.)
Setting Operating Frequency
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:
tOSC =
R osc + 22
µs
25
with ROSC in kΩ
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 sub-harmonic (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
Figure 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 −
⎟
⎜
V
IN(nom ) ⎠ fOSC
⎝
(
)
From this the timing resistor, ROSC, can be calculated: R OSC = t OFF (µs) ∗ 25 − 22(kΩ)
Inductor Selection
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.
L=
(VIN − VLEDs ) × D
(0.3 × ILED ) × fOSC
Where D is duty cycle
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.
AL9910/ AL9910A/ AL9910-5/ AL9910-5A
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AL9910/ AL9910A/ AL9910-5/ AL9910A-5
Applications Information (cont.)
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 45mV 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.
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 15V to 500V. See Figure 3 for typical circuit.
LED +
VAC IN
C1
BR1
C2
VIN
VDD
LD
D1
AL9910/A
PWM_D
ROSC
GND
GATE
C3
L1
LED -
Q1
CS
RSENSE
ROSC
Figure 3. Typical Application Circuit (without PFC)
Buck Design Equations:
D=
VLEDs
VIN
t ON =
L≥
D
fosc
( VIN − VLEDs ) × t ON
0.3 × ILED
RSENSE =
ILED
0.25
where ILED x 0.3 = IRIPPLE
+ (0.5 × (ILED × 0.3))
AL9910/ AL9910A/ AL9910-5/ AL9910-5A
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AL9910/ AL9910A/ AL9910-5/ AL9910A-5
Applications Information (cont.)
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
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 − DCH )
2 × VLINE _ MIN × 2fL × ΔVDC _ MAX
Where
Dch : Capacity charge work period, generally about 0.2 to 0.25
fL : Input frequency for full range (85 to 265VRMS)
ΔVDC _ MAX Should be set 10 to15% 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:
CMIN =
ILED × VLEDs × 0.06
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
VAC IN
VDD
BR1
LD
C2
C3
D1
VIN
AL9910/A
PWM_D
ROSC
GND
Q1
GATE
L1
LED -
CS
RSENSE
ROSC
Figure 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/ AL9910-5A
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AL9910/ AL9910A/ AL9910-5/ AL9910A-5
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.
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
AL9910/A
PWM_D
C2
D1
Q1
LD
ROSC
GATE
CS
C3
GND
ROSC
RSENSE
Figure 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:
VOUT =
VOUT − VIN
VIN
Î D=
VOUT
1− D
From the switching frequency, fOSC, the on-time of the MOSFET can be calculated:
t ON =
D
fOSC
From this the required inductor value can be determined by:
L=
VIN ∗ t 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/ AL9910-5A
Document number: DS35103 Rev. 9 - 2
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AL9910/ AL9910A/ AL9910-5/ AL9910A-5
Ordering Information
AL9910 X XX XX - 13
VCS Tolerance
Variant
Package
Blank : 10%
-5 : 5%
Blank : 7.5V VDD
A : 10V VDD
S : SO-8
SP : SO-8EP
Part Number
VCS Tolerance
Package
Code
Packaging
AL9910-5S-13
AL9910-5SP-13
AL9910A-5S-13
AL9910A-5SP-13
AL9910AS-13
AL9910ASP-13
±5%
±5%
±5%
±5%
±10%
±10%
S
SP
S
SP
S
SP
AL9910S-13
AL9910SP-13
±10%
±10%
S
SP
Packing
13 : 13” Tape & Reel
13” Tape and Reel
SO-8
SO-8EP
SO-8
SO-8EP
SO-8
SO-8EP
Quantity
2500/Tape & Reel
2500/Tape & Reel
2500/Tape & Reel
2500/Tape & Reel
2500/Tape & Reel
2500/Tape & Reel
Part Number Suffix
-13
-13
-13
-13
-13
-13
SO-8
SO-8EP
2500/Tape & Reel
2500/Tape & Reel
-13
-13
Marking Information
(1) SO-8
(Top View)
8
7
6
5
Logo
YY : Year : 08, 09,10~
WW : Week : 01~52; 52
represents 52 and 53 week
X X : Internal Code
9910 XX
Part Number
9910 for 7.5V, 10%
9910-5 for 7.5V, 5%
9910A for 10V, 10%
9910A5 for 10V, 5%
YY WW X X
1
2
3
4
(2) SO8-EP
(Top View)
8
7
6
5
Logo
Part Number
9910 for 7.5V, 10%
9910-5 for 7.5V, 5%
9910A for 10V, 10%
9910A5 for 10V, 5%
9910 X X
YY WW X X E
E : SO-8EP
1
AL9910/ AL9910A/ AL9910-5/ AL9910-5A
Document number: DS35103 Rev. 9 - 2
YY : Year : 08, 09,10~
WW : Week : 01~52; 52
represents 52 and 53 week
X X : Internal Code
2
3
4
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© Diodes Incorporated
AL9910/ AL9910A/ AL9910-5/ AL9910A-5
Package Outline Dimensions (All dimensions in mm.)
Please see AP02002 at http://www.diodes.com/datasheets/ap02002.pdf for latest version.
SO-8
0.254
(1)
E1 E
A1
Gauge Plane
Seating Plane
L
Detail ‘A’
7°~9°
h
45°
Detail ‘A’
A2 A A3
b
e
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
D
(2)
SO-8EP
Exposed Pad
8
5
E1
1
H
4
F
b
Bottom View
9° (All sides)
N
7°
A
e
D
Q
4° ± 3°
A1
AL9910/ AL9910A/ AL9910-5/ AL9910-5A
Document number: DS35103 Rev. 9 - 2
E
45°
E0
C
Gauge Plane
Seating Plane
L
13 of 15
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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
May 2014
© Diodes Incorporated
AL9910/ AL9910A/ AL9910-5/ AL9910A-5
Suggested Pad Layout
Please see AP02001 at http://www.diodes.com/datasheets/ap02001.pdf for the latest version.
(1)
SO-8
X
Dimensions
X
Y
C1
C2
C1
C2
Value (in mm)
0.60
1.55
5.4
1.27
Y
(2)
SO-8EP
X2
Dimensions
C
X
X1
X2
Y
Y1
Y2
Y1
Y2
X1
Y
C
X
AL9910/ AL9910A/ AL9910-5/ AL9910-5A
Document number: DS35103 Rev. 9 - 2
Value
(in mm)
1.270
0.802
3.502
4.612
1.505
2.613
6.500
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AL9910/ AL9910A/ AL9910-5/ AL9910A-5
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).
Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other 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 license under its patent or
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website, harmless against all damages.
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Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall indemnify and
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indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.
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This document is written in English but may be translated into multiple languages for reference. Only the English version of this document is the
final and determinative format released by Diodes Incorporated.
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 systems, and
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements 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
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Copyright © 2014, Diodes Incorporated
www.diodes.com
AL9910/ AL9910A/ AL9910-5/ AL9910-5A
Document number: DS35103 Rev. 9 - 2
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May 2014
© Diodes Incorporated
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