ALPHA-MICRO AMG

AMG-LL9910B
Universal High Voltage Single Channel LED Driver
1. Functional Description of the AMG-LL9910B
The AMG-LL9910B is a universal high voltage LED driver IC. Both buck and boost topologies
are possible. It has one current regulated channel.
The AMG-LL9910B controls an external MOSFET at fixed switching frequencies up to
300 kHz. The frequency can be programmed by using a single resistor. The LED string is
driven at a constant current rather than a constant voltage, thus providing constant light output
and enhanced reliability. The output current to a LED string can be programmed to any value
between 0 and 100% by applying an external control voltage at the linear dimming control
input. The IC provides a low-frequency PWM dimming input that can accept an external
control signal with a duty ratio between 0% and 100% and a frequency of up to a few
kilohertz.
2. Features








Supply voltage 8VDC … 450VDC
>90 % efficiency
8 – 450V input voltage
Peak current mode converter
Linear and PWM dimming capability
Buck and Boost topology
Pin compatible with other HV LED drivers
SOP8 Package with exposed pad for a lower thermal resistance
3. Application
The AMG-LL9910B is suitable for:
 DC/DC or AC/DC LED driver applications
 LED backlighting
 General-purpose LED lighting
 General-purpose constant current source
 Battery chargers
AMG-LL9910B
Revision: B
09/13/12
© All rights reserved
Page 1 of 15
AMG-LL9910B
Universal High Voltage Single Channel LED Driver
3.1. Example Application Drawing
Vin DC
Vin
Vdd
LD
AMG
LL9910B
PWMD
Gate
Rosz
CS
GND
Figure 1: Buck LED Driver
AMG-LL9910B
Revision: B
09/13/12
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AMG-LL9910B
Universal High Voltage Single Channel LED Driver
Table of Contents
1.Functional Description of the AMG-LL9910B......................................................................... 1
2.Features................................................................................................................................. 1
3.Application............................................................................................................................. 1
3.1.Example Application Drawing................................................................................................... 2
4.Block Diagram....................................................................................................................... 4
5.Block Descriptions................................................................................................................. 4
6.Pinning................................................................................................................................... 5
7.Absolute Maximum Ratings................................................................................................... 6
8.Electrical Characteristics........................................................................................................ 6
8.1.Operational Range................................................................................................................... 6
8.2.DC Characteristics................................................................................................................... 7
8.3.AC Characteristics.................................................................................................................... 7
9.Application............................................................................................................................. 8
9.1.Example Application Circuit...................................................................................................... 8
9.2.Application Notes..................................................................................................................... 8
9.3.Off Line LED Driver................................................................................................................. 11
9.4.Off Line LED Driver with Digital I/F.........................................................................................11
9.5.Off Line LED Driver with Temp-Protection..............................................................................12
9.6.Battery Powered LED Driver..................................................................................................12
10.Ordering Information.......................................................................................................... 13
11.IC-Package........................................................................................................................ 13
12.IC-Marking......................................................................................................................... 13
13.Notes and Cautions........................................................................................................... 14
13.1.ESD Protection..................................................................................................................... 14
13.2.Storage conditions................................................................................................................ 14
14.Disclaimer.......................................................................................................................... 14
15.Contact Information............................................................................................................ 15
AMG-LL9910B
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09/13/12
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AMG-LL9910B
Universal High Voltage Single Channel LED Driver
4. Block Diagram
Regulator
Vin
LD
+
CS
POR +
UVLO
1
&
Blanking
+
R
Gate
Q
S
-
250mV
Vdd
Oscillator
PWMD
GND
Rosc
Figure 2: Block Diagram
5. Block Descriptions
Linear Regulator
Generates a stable supply for the logic. May also supply external circuitry.
POR + UVLO
Power on Reset and Under Voltage lockout. The IC is released from reset, after the Vdd rises
above the UVLO voltage.
Linear Dimming Comparator
Manual setting of the VCS threshold.
Current Sense Comparator
Current limiting comparator.
Blanking Timer
Inserts a time delay from CS trip to Gate low, in order to enable100% duty cycle.
AMG-LL9910B
Revision: B
09/13/12
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AMG-LL9910B
Universal High Voltage Single Channel LED Driver
RS Flip Flop
Enables and disables the gate driver. Set by the oscillator, reset by current limit.
Gate Driver
Drives external MOSFET. Gated by external PWM or enable signal.
Oscillator
Determines PWM frequency.
6. Pinning
Vin
Supply input
2
CS
Current Sense
3
GND
Ground
4
Gate
Driver output for external MOSFET
5
PWMD
PMW dimming input
6
Vdd
Linear regulator output
7
LD
Linear Dimming
8
Rosc
Resistor to GND setting Oscillator Frequency
EP
-
Thermal conductive pad on the bottom. Connect this pad to Ground,
and provide sufficient thermal coupling to remove heat from the
package.
D M WP
1
dd V
Description
DL
Symbol
cs o R
PIN#
αLL9910
YYWW
XXXX
et a G
AMG-LL9910B
DN G
SC
ni V
1
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09/13/12
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AMG-LL9910B
Universal High Voltage Single Channel LED Driver
7. Absolute Maximum Ratings
The Absolute Maximum Ratings may not be exceeded under any circumstances.
#
Symbol
Parameter
Min
Max
Unit
1
Vin
Supply input voltage
-0.5
470
V
2
Vlogic
Voltage on CS, LD, PWMD, Gate
-0.3
Vdd + 0.3
V
3
Tj
Junction temperature
150
°C
4
TS
Storage temperature
-65
150
°C
5
Vddmax
Max. voltage at Vdd
-0.3
12
V
6
Rthja
Thermal resistance junction ambient
42
K/W
7
[email protected]°C
Total power dissipation
2.5
W
Unit
Note: All voltages are with respect to GND
8. Electrical Characteristics
8.1. Operational Range
(Ta=25°C unless noted otherwise)
#
Symbol
1
Vin
1)
2
3
Note:
Parameter
Min
Max
Supply input voltage
10
450
Ta
Operating ambient temperature
-40
125
PWM
Duty Cycle
1)
100
V
1) 2)
°C
%
Also limited by maximum power dissipation, whichever is lower.
2)
Rthja = (Tj –Ta) / Ptot
AMG-LL9910B
Revision: B
09/13/12
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AMG-LL9910B
Universal High Voltage Single Channel LED Driver
8.2. DC Characteristics
(Ta=25°C unless noted otherwise)
#
Symbol
Parameter
Min
Typ
Max
Unit
1
Vdd
Regulator output voltage
7.25
7.5
7.75
V
2
Iext
3)
0.7
mA
3
UVLO
Undervoltage lockout (Vdd rising)
6.95
V
4
ΔUVLO
Undervoltage lockout hysteresis (Vdd falling)
5
Vin low
Input voltage logic low (PWMD)
6
Vin high
Input voltage logic high (PWMD)
2
7
RPWMD
Pull down on PWMD pin
50
100
150
kΩ
8
Vcs
Current sense threshold
225
250
275
mV
10
Vgate low
Gate driver low output voltage (@10mA)
0
0.3
V
11
Vgate high
Gate driver high output voltage (@-10mA)
Vdd-0.3
Vdd
V
12
Idd
Current consumption (shutdown), VPWM =0V
0.5
1
mA
Note:
3)
Current for ext. circuitry (10V < Vin < 100V)
6.45
6.7
500
mV
0.8
V
V
Also limited by maximum power dissipation, whichever is lower.
8.3. AC Characteristics
(Ta=25°C unless noted otherwise)
#
Symbol
Parameter
Min
Typ
Max
Unit
1
fOSC
Oscillator frequency @ ROSC=1000kOhm
20
25
30
kHz
Oscillator frequency @ ROSC=226kOhm
80
100
120
kHz
2
tblank
Minimal gate on time (Current sense blanking time)
150
215
280
ns
3
tdelay
Time from CS trip to Gate low
80
150
ns
4
trise
Gate driver output rise time (Cgate = 500pF)
30
50
ns
5
tfall
Gate driver output fall time (Cgate = 500pF)
30
50
ns
AMG-LL9910B
Revision: B
09/13/12
© All rights reserved
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AMG-LL9910B
Universal High Voltage Single Channel LED Driver
9. Application
9.1. Example Application Circuit
Vin DC
Vin
Vdd
LD
AMG
LL9910B
PWMD
Gate
Rosc
CS
GND
Figure 3: Buck LED Driver
9.2. Application Notes
a) Peak Current Regulation
The oscillator resistor sets the PWM frequency. After each oscillator period, the gate driver is
pulled high and the duty cycle begins.
When the current over sense resistor RCS reaches the current limit, the current sense
comparator will trip and after blanking time the gate driver output is pulled low and the duty
cycle ends.
Smaller inductors and lower PWM frequencies will provide for higher current ripple. In the
case that the highest light intensity is desired, the ripple should be maximized and the LED
driven to it's specified peak current limit.
In the case that the highest efficacy and longest LED lifetime is desired, the LED needs to be
driven to the optimum current value only. In this situation, the ripple should be kept as low as
possible. Bigger inductor values and higher PWM frequencies will help achieve this result.
AMG-LL9910B
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09/13/12
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AMG-LL9910B
Universal High Voltage Single Channel LED Driver
b) LED Current
The maximum LED current is programmed with an external resistor RCS.
If peak current for highest light intensity is desired, the resistor value should be calculated as
follows:
RCS = 250mV/ILED peak
If an average current for highest efficacy and longest lifetime is desired, the resistor value
should be calculated as follows:
RCS = 250mV/[ILED avg + (0.5*ΔIL)]
ΔIL = Iripple
c) Inductor Value
The inductor value depends on the input voltage, output voltage, PWM frequency and the
desired current ripple.
First , we calculate the ratio between input and output voltage and the voltage over the
inductor. The input voltage is the average supply voltage for the IC while the output voltage is
the number of LEDs on the string times the LED forward voltage.
Vout = n * VF
VL = Vin - Vout
Please note: that the forward LED voltage is a function of the LED current. The LED data
sheet should provide the corresponding forward voltage for a given LED current.
D = Vout/Vin
For a buck design, D must be lower than 1.
Then, the ripple of the LED currents needs to be determined, which will then provide the
actual inductor value.
For the maximum peak current (highest intensity), a current ripple higher than 50% (0.5) is
desirable.
ΔIL = ripple * ILED peak
Inductor values should be rounded down in this case.
For a stable average current (highest efficacy), a current ripple lower than 20% (0.2) is
desirable.
ΔIL = ripple * ILED avg
Inductor values should be rounded up for this case.
L= (D/fosc) * (VL/ΔIL)
AMG-LL9910B
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09/13/12
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AMG-LL9910B
Universal High Voltage Single Channel LED Driver
d) Linear Dimming
If the second comparator is provided with a threshold voltage lower than the internal threshold
voltage of the first comparator, the current over the LED can be manually adjusted. This can
be achieved with any analog voltage between 0 and the internal reference voltage (e.g. with a
potentiometer).
e) Digital Dimming
With an external PWM signal at the PWMD pin, the gate driver can be gated. This means, the
LED will light up during the duty cycle of the external PWM signal and vice versa, the LED will
be off during the off-time of the external PWM signal.
The external PWM frequency needs to be much smaller than the frequency of the
AMG-LL9910B. The external PWM frequency should be at least 10x smaller, otherwise
fluctuation effects may occur.
The PWMD pin may also be used to enable or disable the device. The IC is enabled, when
PWMD is pulled to Vcc. It is disabled, when PWMD is pulled to GND:
f) PWM Frequency
FPWM [kHz] = 25000/(Rosc [kΩ]+22)
g) PFC
The AMG-LL9910B does not have a PFC integrated stage. As such, a PFC is usually
necessary for off line LED drivers. This can be either a passive PFC or even an active one,
when the power increases relatively high.
AMG-LL9910B
Revision: B
09/13/12
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AMG-LL9910B
Universal High Voltage Single Channel LED Driver
9.3. Off Line LED Driver
10mH
22µF / 400V
325V DC
UF4007
350mA
Vin
Vdd
82k
Enable
AMG
LL9910B
LD
PWMD
e.g.. IRFxxx
Gate
3k
4,7 µF
Rosc
CS
GND
0,7R
220k
Figure4: Buck topology, linear dimming, enable switch
9.4. Off Line LED Driver with Digital I/F
10mH
325V DC
UF4007
22µF / 400V
350mA
Vin
Vdd
Enable
LD
PWM in
AMG
LL9910B
PWMD
4,7 µF
Gate
e.g. IRFxxx
10k
Rosc
CS
GND
0,7R
220k
Figure 5: Buck topology, digital dimming, enable signal
AMG-LL9910B
Revision: B
09/13/12
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AMG-LL9910B
Universal High Voltage Single Channel LED Driver
9.5. Off Line LED Driver with Temp-Protection
10mH
22µF / 400V
325V DC
UF4007
350mA
Vin
Vdd
33k
LD
AMG
LL9910B
PWMD
Thermally
connect
to LEDs
e.g. IRFxxx
Gate
1k NTC
Rosc
ϑ
CS
GND
4,7 µF
0,7R
220k
Figure 6: Buck topology, with Temp-Protection
9.6. Battery Powered LED Driver
47µF / 16V
12V DC
1mH
UF4004
Vin
Vdd
10µF / 60V
AMG
LL9910B
LD
PWMD
Gate
e.g. IRFxxx
4,7 µF
Rosc
CS
GND
350mA
0,3R
100k
Figure 7: Boost topology
AMG-LL9910B
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09/13/12
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AMG-LL9910B
Universal High Voltage Single Channel LED Driver
10. Ordering Information
AMG-LL9910B-ISO08U
SOP8 in tubes
AMG-LL9910B-ISO08R
SOP8 in tape and reel
11. IC-Package
SOP8 with exposed pad
4.90±0.10
6.00±0.20
Exposed Pad
3.90±0.10
Exposed Pad
Not connected
with any of the
leads
1.27
0.42±0.09
0.00 ...
0.10 1.50±0.10
0.22±0.03
All dimensions in mm
12. IC-Marking
αLL9910
4 digit date code
4 … 6 digit lot code
AMG-LL9910B
Revision: B
09/13/12
© All rights reserved
Page 13 of 15
AMG-LL9910B
Universal High Voltage Single Channel LED Driver
13. Notes and Cautions
13.1. ESD Protection
The Requirements for Handling Electrostatic Discharge Sensitive Devices are described in the
JEDEC standard JESD625-A. Please note the following recommendations:
 When handling the device, operators must be grounded by wearing a grounded wrist strap
with at least 1MΩ resistance with direct skin contact.
 Operators must at all times, wear ESD protective shoes or the area should be surrounded by
ESD protected floor mats.
 The opening of an EDS protective package or device must only occur on a properly equipped
ESD workbench. The tape with which the package is held together must be cut with a sharp
cutting tool, never pulled or ripped off.
 Any unnecessary contact with the device or any unprotected conductive points should be
avoided.
 Only work with qualified and grounded tools, measuring equipment, casings and
workbenches.
 When outside of properly protected ESD-areas, the device or any electronic assembly must
be protected and always be transported in EGB/ESD shielded packaging.
13.2. Storage conditions
The AMG-LL9910B corresponds to moisture sensitivity classification ML2, according to JEDEC
standard J-STD-020, and should be handled and stored according to J-STD-033.
14. Disclaimer
Information given in this data sheet is believed to be accurate and reliable. However, no
responsibility is assumed for the consequences of its use nor for any infringement of patents or
other rights of third parties that may result from its use.
The values stated in Absolute Maximum Ratings may under no circumstances be exceeded. No
warranty is given for use in life support systems or medical equipment without the specific written
consent of alpha microelectronics gmbh. For questions regarding the application please contact
the publisher.
The declared data are only a description of the product. They are not guaranteed properties as
defined by law. Samples are provided without obligation and cannot give rise to any liability.
Reprinting of this data sheet – or any part of it – is not allowed without the license of the publisher.
Data sheets are subject to change without any notice.
AMG-LL9910B
Revision: B
09/13/12
© All rights reserved
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AMG-LL9910B
Universal High Voltage Single Channel LED Driver
15. Contact Information
This data sheet is published by alpha microelectronics gmbh. To order samples or inquire
information please contact:
alpha microelectronics gmbh
Im Technologiepark 1
15236 Frankfurt (Oder)
Germany
[email protected]
www.alpha-microelectronics.de
+49-335-557-1750 (telephone)
+49-335-557-1759 (fax)
© All rights reserved.
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Revision: B
09/13/12
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