HV9910NG [SUPERTEX]
Universal High Brightness LED Driver; 通用高亮度LED驱动器
| 型号： | HV9910NG |
| 厂家： | 
Supertex, Inc |
| 描述： | Universal High Brightness LED Driver |
| 文件： | 总11页 (文件大小：436K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
HV9910
Universal High Brightness LED Driver
Description
Features
The HV9910 is a PWM high-efficiency LED driver
control IC. It allows efficient operation of High
Brightness (HB) LEDs from voltage sources
ranging from 8VDC up to 450VDC. The HV9910
controls an external MOSFET at fixed switching
frequency up to 300kHz. The frequency can be
programmed using a single resistor. The LED string
is driven at constant current rather than constant
voltage, thus providing constant light output and
enhanced reliability. The output current can be
programmed between a few milliamps and up to
more than 1.0A.
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>90% Efficiency
8V to 450V input range
Constant-current LED driver
Applications from a few mA to more than 1A
Output
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LED string from one to hundreds of diodes
PWM Low-Frequency Dimming via Enable pin
Input Voltage Surge ratings up to 450V
HV9910 uses a rugged high voltage junction
isolated process that can withstand an input voltage
surge of up to 450V. Output current to an LED
string can be programmed to any value between
zero and its maximum value by applying an
external control voltage at the linear dimming
control input of the HV9910. The HV9910 provides
a low-frequency PWM dimming input that can
accept an external control signal with a duty ratio of
0-100% and a frequency of up to a few kilohertz.
Applications
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DC/DC or AC/DC LED Driver applications
RGB Backlighting LED Driver
Back Lighting of Flat Panel Displays
General purpose constant current source
Signage and Decorative LED Lighting
Automotive
Chargers
Typical Application
C110504
HV9910
Ordering Information
Package Options
DIP-8
SO-16
SO-8
HV9910NG
HV9910P
HV9910LG
Absolute Maximum Ratings
VIN to GND ...................................….........................-0.5V to +470V
CS.....................…………………………………...-0.3V to Vdd + 0.3V
LD, PWM_D to GND...........……........…............-0.3V to (Vdd --0.3V)
GATE to GND .................................………......-0.3V to (Vdd + 0.3V)
VDDMAX…………………………………………………………..……13.5V
Continuous Power Dissipation (TA = +25°C) (Note 1)
16-Pin SO (derate 7.5mW/°C above +25°C).…...…….….....750mW
8-Pin DIP (derate 9mW/°C above +25°C)…..……..…….......900mW
8-Pin SO (derate 6.3mW/°C above +25°C)…..……..…….....630mW
Operating Temperature Range ...................……......-40°C to +85°C
Junction Temperature....................................……….............+125°C
Storage Temperature Range .......................……...-65°C to +150°C
Stresses beyond those listed under ‘‘Absolute Maximum Ratings’’ may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Specifications (TA = 25°C unless noted otherwise)
Symbol Description
Min
Typ
Max
450
1
Units
V
Conditions
VINDC
IINsd
Input DC supply voltage range
8.0
DC input voltage
Shut-Down mode supply current
Internally regulated voltage
0.5
7.5
mA
Pin PWM_D to GND, VIN = 8V
VIN = 8–450V, IDD(ext)=0, pin Gate
open
When an external voltage applied
to pin Vdd
VDD
7.0
8.0
V
V
VDDmax
Maximal pin Vdd voltage
13.5
IDD(ext)
UVLO
∆UVLO
VEN(lo)
VEN(hi)
REN
VDD current available for external circuitry 1
VDD undervoltage lockout threshold
VDD undervoltage lockout hysteresis
Pin PWM_D input low voltage
Pin PWM_D input high voltage
Pin PWM_D pull-down resistance
Current sense pull-in threshold voltage
GATE high output voltage
1.0
mA
V
VIN = 8–100V
Vin rising
6.45
6.7
6.95
500
mV
V
Vin falling
1.0
VIN = 8–450V
VIN = 8–450V
VEN = 5V
2.4
50
V
100
250
150
275
VDD
0.3
kΩ
mV
V
VCS(hi)
VGATE(hi)
VGATE(lo)
fOSC
225
VDD-0.3
0
@TA = -40°C to +85°C
IOUT = 10mA
IOUT = -10mA
GATE low output voltage
V
Oscillator frequency
20
80
25
100
30
120
kHz
kHz
ROSC = 1.00MΩ
ROSC = 226kΩ
FPWMhf = 25kHz, at GATE, CS to
GND. GBD
DMAXhf
Maximum Oscillator PWM Duty Cycle
100
%
VLD
Linear Dimming pin voltage range
Current sense blanking interval
0
250
280
mV
ns
@TA = <85°C, Vin = 12V
TBLANK
150
215
VCS = 0.55VLD, VLD = VDD
Vin = 12V, VLD = 0.15, VCS = 0 to
0.22V after TBLANK
tDELAY
Delay from CS trip to GATE lo
300
ns
tRISE
tFALL
GATE output rise time
GATE output fall time
30
30
50
50
ns
ns
CGATE = 500pF
CGATE = 500pF
1 Also limited by package power dissipation limit, whichever is lower.
2
C110504
HV9910
Pinout
Description
SO-16
SO-8
DIP-8
1
2
3
4
Name
VIN
CS
GND
GATE
1
4
5
8
Input voltage 8V to 450V DC
Senses LED string current
Device ground
Drives the gate of the external MOSFET
Low Frequency PWM Dimming pin, also Enable
input. Internal 100kΩ pull-down to GND
8-Pin DIP/SOIC
PWM_D
9
5
Internally regulated supply voltage. 7.5V
nominal. Can supply up to 1mA for external
circuitry. A sufficient storage capacitor is used to
provide storage when the rectified AC input is
near the zero crossings.
VDD
12
6
Linear Dimming by changing the current limit
threshold at current sense comparator
Oscillator control. A resistor connected between
this pin and ground sets the PWM frequency.
LD
13
14
7
8
ROSC
No Connects (NC) are not internally connected and may be used for pass-thru PCB traces.
16-Pin SOIC
Block Diagram & Typical Application
3
C110504
HV9910
the sense resistor is applied to the CS pin of the
HV9910. When the voltage at CS pin exceeds a
peak current sense voltage threshold, the gate
drive signal terminates, and the power MOSFET
turns off. The threshold is internally set to 250mV,
or it can be programmed externally by applying
voltage to the LD pin. When soft start is required, a
capacitor can be connected to the LD pin to allow
this voltage to ramp at a desired rate, therefore,
assuring that output current of the LED ramps
gradually.
Application Information
AC/DC Off-Line Applications
The HV9910 is a low-cost off-line buck, boost or
buck-boost converter control IC specifically
designed for driving multi-LED stings or arrays. It
can be operated from either universal AC line or
any DC voltage between 8-450V. Optionally, a
passive power factor correction circuit can be used
in order to pass the AC harmonic limits set by EN
61000-3-2 Class C for lighting equipment having
input power less than 25W. The HV9910 can drive
up to hundreds of High-Brightness (HB) LEDs or
multiple strings of HB LEDs. The LED arrays can
be configured as a series or series/parallel
connection. The HV9910 regulates constant current
that ensures controlled brightness and spectrum of
the LEDs, and extends their lifetime. The HV9910
features an enable pin (PWM_D) that allows PWM
control of brightness.
Optionally, a simple passive power factor correction
circuit, consisting of 3 diodes and 2 capacitors, can
be added as shown in the application circuit
diagram of Figure 1.
Supply Current
A current of 1mA is needed to start the HV9910. As
shown in block diagram, this current is internally
generated in HV9910 without using bulky startup
resistors typically required in the offline
applications. Moreover, in many applications the
HV9910 can be continuously powered using its
internal linear regulator that provides a regulated
voltage of 7.5V for all internal circuits.
The HV9910 can also control brightness of LEDs
by programming continuous output current of the
LED driver (so-called linear dimming) when a
control voltage is applied to the LD pin.
The HV9910 is offered in standard 8-pin SOIC and
DIP packages. It is also available in a high voltage
rated SO-16 package for applications that require
VIN greater than 250V.
Setting Light Output
When the buck converter topology of Figure 1 is
selected, the peak CS voltage is
a
good
representation of the average current in the LED.
However, there is a certain error associated with
this current sensing method that needs to be
accounted for. This error is introduced by the
difference between the peak and the average
current in the inductor. For example if the peak-to-
peak ripple current in the inductor is 150mA, to get
a 500mA LED current, the sense resistor should be
250mV/(500mA+ 0.5*150mA)=0.43Ω.
The HV9910 includes an internal high-voltage
linear regulator that powers all internal circuits and
can also serve as a bias supply for low voltage
external circuitry.
LED Driver Operation
The HV9910 can control all basic types of
converters, isolated or non-isolated, operating in
continuous or discontinuous conduction mode.
When the gate signal enhances the external power
MOSFET, the LED driver stores the input energy in
an inductor or in the primary inductance of a
transformer and, depending on the converter type,
may partially deliver the energy directly to LEDs
The energy stored in the magnetic component is
further delivered to the output during the off-cycle of
the power MOSFET producing current through the
string of LEDs (Flyback mode of operation).
Dimming
Dimming can be accomplished in two ways,
separately or combined, depending on the
application. Light output of the LED can be
controlled either by linear change of its current, or
by switching the current on and off while
maintaining it constant. The second dimming
method (so-called PWM dimming) controls the LED
brightness by varying the duty ratio of the output
current.
When the voltage at the VDD pin exceeds the UVLO
threshold the gate drive is enabled. The output
current is controlled by means of limiting peak
current in the external power MOSFET. A current
sense resistor is connected in series with the
source terminal of the MOSFET. The voltage from
The linear dimming can be implemented by
applying a control voltage from 0 to 250mV to the
LD pin. This control voltage overrides the internally
set 250mV threshold level of the CS pin and
programs the output current accordingly. For
4
C110504
HV9910
example, a potentiometer connected between VDD
and ground can program the control voltage at the
CS pin. Applying a control voltage higher than
250mV will not change the output current setting.
When higher current is desired, select a smaller
sense resistor.
The PWM dimming scheme can be implemented by
applying an external PWM signal to the PWM_D
pin. The PWM signal can be generated by a
microcontroller or a pulse generator with a duty
cycle proportional to the amount of desired light
output. This signal enables and disables the
converter modulating the LED current in the PWM
fashion. In this mode, LED current can be in one of
the two states: zero or the nominal current set by
the current sense resistor. It is not possible to use
this method to achieve average brightness levels
higher than the one set by the current sense
threshold level of the HV9910. By using the PWM
control method of the HV9910, the light output can
be adjusted between zero and 100%. The accuracy
of the PWM dimming method is limited only by the
minimum gate pulse width, which is a fraction of a
percent of the low frequency duty cycle.
95% PWM Ratio at 500Hz Dimming
Some of the typical waveforms illustrating the PWM
dimming method used with the application circuit of
Figure 1 are given below. CH1 shows the MOSFET
Drain voltage, CH2 is the PWM signal to pin
PWM_D and CH4 is the current in the LED string.
0.4% PWM Ratio at 500Hz Dimming
Programming Operating Frequency
The operating frequency of the oscillator is
programmed between 25 and 300kHz using an
external resistor connected to the ROSC pin:
FOSC = 25000/(ROSC [kΩ] + 22) [kHz]
Power Factor Correction
When the input power to the LED driver does not
exceed 25W, a simple passive power factor
correction circuit can be added to the HV9910
application circuit of Figure 1 in order to pass the
AC line harmonic limits of the EN61000-3-2
standard for Class C equipment. The typical
application circuit diagram shows how this can be
done without affecting the rest of the circuit
significantly. A simple circuit consisting of 3 diodes
and 2 capacitors is added across the rectified AC
line input to improve the line current harmonic
distortion and to achieve a power factor greater
than 0.85.
33% PWM Ratio at 500Hz Dimming
5
C110504
HV9910
The required value of the inductor is given by:
Inductor Design
Referring to the Typical Application Circuit below
the value can be calculated from the desired peak-
to-peak LED ripple current in the inductor.
Typically, such ripple current is selected to be 30%
of the nominal LED current. In the example given
here, the nominal current ILED is 350mA.
L = (Vin - VLEDs) * Ton/(0.3 * ILED) = 4.6mH
Input Bulk Capacitor
An input filter capacitor should be designed to hold
the rectified AC voltage above twice the LED string
voltage throughout the AC line cycle. Assuming
15% relative voltage ripple across the capacitor, a
simplified formula for the minimum value of the bulk
input capacitor is given by:
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.
Cmin = ILED*VLEDs*0.06/VIN^2
Cmin = 22 µF, a value 22uF/250V can be used.
Knowing the nominal rectified input voltage
VIN=120V*1.41=169V, the switching duty ratio can
be determined, as:
A passive PFC circuit at the input requires using
two series connected capacitors at the place of
calculated CMIN. Each of these identical capacitors
should be rated for ½ of the input voltage and have
twice as much capacitance.
D= VLEDs /VIN=30/169=0.177
Then, given the switching frequency, in this
example fosc=50KHz, the required on-time of the
MOSFET transistor can be calculated:
Enable
The HV9910 can be turned off by pulling the
PWM_D pin to ground. When disabled, the HV9910
draws quiescent current of less than 1mA.
Ton=D/fosc=3.5 microsecond
Figure 1: Typical Application Circuit
1N4004
1N4004
2A,
coilcraft
BYV26B
250 V
BUSH-2820R5B
1N4004
LEDs
68µ F,
160 V
VIN
RT
AC Input
85-135V AC
750µΗ
,
VDD
F,
F,
0.1µ
0.1µ
280 kΩ
1µF,
10V
250 V
250 V
HV9910
1N4004
2R
NTC
1n F,
250 V
VN2224
GATE
CS
220nF,
400 V
F,
160 V
68µ
1n F,
250 V
1N4004
1N4004
LD
0.2
Ω
optional for PFC
GND
PWM_D
LED(s) – a string of HB LEDs , 16 diodes
6
C110504
HV9910
Output Open Circuit Protection
The output voltage can be either higher or lower
than the input voltage, depending on duty ratio.
When the buck topology is used, and the LED is
connected in series with the inductor, there is no
need for any protection against an open circuit
condition in the LED string. Open LED connection
means no switching and can be continuous.
However, in the case of the buck-boost or the
Flyback topology the HV9910 may cause excessive
voltage stress of the switching transistor and the
rectifier diode and potential failure. In this case, the
HV9910 can be disabled by pulling the PMW_D pin
to ground when the over voltage condition is
detected.
Let us discuss the above example of an automotive
LED driver that needs to drive three HB LEDs at
350mA.
Knowing the nominal input voltage VIN=12V, the
nominal duty ratio can be determined, as
D=VLEDs/(VIN+VLEDs)=9/(12+9)=0.43
Then, given the switching frequency, in this
example fOSC=50KHz, the required on-time of the
MOSFET transistor can be calculated:
DC/DC Low Voltage Applications
Ton=D/fOSC=8.6 microsecond
The required value of the inductor is given by:
L = VIN* Ton/(0.3 * Iled) = 0.98mH, use 1mH
Buck Converter Operation
The buck power conversion topology can be used
when the LED string voltage is needed to be lower
than the input supply voltage. The design
procedure for a buck LED driver outlined in the
previous chapters can be applied to the low voltage
LED drivers as well. However, 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 HV9910 buck converter operates at a duty
cycle greater than 0.5. This instability reveals itself
as an oscillation of the output current at a sub-
harmonic of the switching frequency.
Output Capacitor
Unlike the buck topology, the buck-boost converter
requires an output filter capacitor to deliver power
to the LED string during the ON time of switching
the transistor, when the Flyback inductor current is
diverted from the output of the converter.
In order to average the current in the LED, this
capacitor must present impedance to the switching
output AC ripple current that is much lower than the
dynamic impedance ROUT of the LED string. If we
assume ROUT=3 Ohm in our example, in order to
attenuate the switching ripple by a factor of 10, a
capacitor with equivalent series resistance (ESR) of
0.3 Ohm is needed. A chip SMT tantalum capacitor
can be selected for this purpose.
Flyback (Buck-Boost) Operation
This power conversion topology can be used when
the forward voltage drop of the LED string is higher,
equal or lower than the input supply voltage. For
example, the buck-boost topology can be
appropriate when input voltage is supplied by an
automotive battery (12V) and output string consists
of three to six HB LEDs, as the case may be for tail
and break signal lights.
In the buck-boost converter, the energy from the
input source is first stored in the inductor or a
Flyback transformer when the switching transistor
is ON. The energy is then delivered to the output
during the OFF time of the transistor. When the
energy stored in the Flyback 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 = - VIN*D/(1-D)
7
C110504
HV9910
Figure 2 - HV9910 Buck Driver for a single 900mA HB LED (VIN = 8 – 30V)
Figure 3 - HV9910 Buck-Boost driver powering 3 to 8, 350mA HB LEDs (VIN = 8 – 30VIN)
C110504
Doc. #: DSFPHV9910
Package Outlines
8-LEAD PLASTIC DUAL IN-LINE PACKAGE (P)
0.040
(1.016)
TYP
0.395 max
0.250
± 0.015
0.250
± 0.005
0.030 -
0.110
1
0.300 - 0.320
0.130 ± 0.005
0.020
0.125 min.
0° - 10°!
0.020 min.
0.009 - 0.015
0.018 ± 0.003
0.100 ± 0.010
+0.025
0.325
-0.015
Dimensions in Inches
Measurement Legend =
Note: C ircle (e.g. B ) indicates J E DE C R eference.
(Dimensions in Millimeters)
Doc. #: DSPD8PDP
A051004
1235 B ordeaux Drive, S unnyvale, C A 94089
TE L: (408) 222-8888 / F AX: (408) 222-4895
www.supertex.com
©2004 S upertex Inc. All rights reserved. Unauthorized use or reproduction prohibited.
Package Outlines
8-LEAD SMALL OUTLINE PACKAGE (LG, TG) (MS-012AA)
0.192 ± 0.005
(4.8895 ± 0.1143)
D
H
0.236 ± 0.008
(5.9944 ± 0.2032)
H
E
1
0.154 ± 0.004
(3.9116 ± 0.1016)
0.193 ± 0.012
(4.9022 ± 0.3048)
0.020 ± 0.009
h
7° (4 P LC S )
(0.508 ± 0.2286)
0.010 ± 0.002
(0.254 ± 0.0508)
C
45°
0.061 ± 0.008
(1.5494 ± 0.2032)
A
L
1
0° - 8 °
e
B
A
1
0.0275 ± 0.0025
(0.6985 ± 0.0635)
L
0.050
(1.270)
0.016 ± 0.002
(0.4064 ± 0.0508)
0.035 ± 0.015
(0.889 ± 0.381)
0.007 ± 0.003
(0.1778 ± 0.0762)
TYP.
Dimensions in Inches
Measurement Legend =
Note: C ircle (e.g. B ) indicates J E DE C R eference.
(Dimensions in Millimeters)
Doc. #: DSPD8SOLGTG
A051004
1235 B ordeaux Drive, S unnyvale, C A 94089
TE L: (408) 222-8888 / F AX: (408) 222-4895
www.supertex.com
©2004 S upertex Inc. All rights reserved. Unauthorized use or reproduction prohibited.
Package Outlines
16-LEAD SO PACKAGE (NG) (NARROW BODY)
0.3895 ± 0.0045
(9.8935 ± 0.1145)
D
0.2335 ± 0.0105
(5.931 ± 0.267)
0.156 ± 0.002
(3.962 ± 0.051)
E
H
0.193 ± 0.012
(4.9022 ± 0.3048)
0.500
(12.700)
0.350
(8.890)
TYP.
TYP.
D
1
0.0255 ± 0.0005
(0.6475 ± 0.0125)
A
3
0.013 ± 0.004
(0.3302 ± 0.1016)
h
7° (4 P LC S )
45°
0.065 ± 0.004
(1.651 ± 0.102)
0.009 ± 0.002
(0.216 ± 0.038)
C
A
A
2
0° - 8 °
7° (4 P LC S )
e
B
0.059 ± 0.002
L
(1.499 ± 0.051)
L
1
S
0.006 ± 0.002
(0.1524 ± 0.0508)
0.033 ± 0.017
(0.8382 ± 0.4318)
0.0275 ± 0.0025
(0.6985 ± 0.0635)
0.020 ± 0.002
(0.508 ± 0.0508)
0.0165 ± 0.0035
(0.4191 ± 0.0889)
0.050
(1.270)
A
1
TYP.
Dimensions in Inches
Measurement Legend =
Note: C ircle (e.g. B ) indicates J E DE C R eference.
(Dimensions in Millimeters)
Doc. #: DSPD16SONG
A051004
1235 B ordeaux Drive, S unnyvale, C A 94089
TE L: (408) 222-8888 / F AX: (408) 222-4895
www.supertex.com
©2004 S upertex Inc. All rights reserved. Unauthorized use or reproduction prohibited.
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