HV9910NG-G [SUPERTEX]
Universal High Brightness LED Driver; 通用高亮度LED驱动器
| 型号： | HV9910NG-G |
| 厂家： | 
Supertex, Inc |
| 描述： | Universal High Brightness LED Driver |
| 文件： | 总8页 (文件大小：579K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
HV9910
Universal High Brightness
LED Driver
Features
► >90% Efficiency
► 8V to 450V input range
► Constant-current LED driver
► Applications from a few mA to more than 1A
Output
► LED string from one to hundreds of diodes
► PWM Low-Frequency Dimming via Enable pin
► Input Voltage Surge ratings up to 450V
General Description
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.
Applications
The 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.
► 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
VIN
VDD
HV9910
LD
GATE
PWMD
RT
CS
GND
HV9910
Ordering Information
Package Options
SOIC-16 SOIC-8
HV9910NG-G HV9910LG-G
Device
HV9910
-G indicates package is RoHS compliant (‘Green’)
Absolute Maximum Ratings
Pin Configurations
Parameter
VIN to GND
CS
Value
NC
VIN
NC
NC
CS
-0.5V to +470V
-0.3V to (VDD + 0.3V)
-0.3V to (VDD - 0.3V)
-0.3V to (VDD + 0.3V)
13.5V
NC
ROSC
LD
LD, PWM_D to GND
GATE to GND
VDDMAX
VIN
CS
ROSC
LD
GND
NC
VDD
NC
Continuous Power Dissipation (TA = +25°C) (Note 1)
16-Pin SO (derate 7.5mW/°C above +25°C)
8-Pin SO (derate 6.3mW/°C above +25°C)
Operating temperature range
GND
GATE
VDD
NC
NC
750mW
630mW
PWM_D
GATE
PWM_D
8-Lead SOIC
16-Lead SOIC
-40°C to +85°C
+125°C
Junction temperature
Storage temperature range
-65°C to +150°C
Absolute Maximum Ratings are those values beyond which damage to the device may
occur. Functional operation under these conditions is not implied. Continuous operation
of the device at the absolute rating level may affect device reliability. All voltages are
referenced to device ground.
Electrical Characteristics
(Over recommended operating conditions unless otherwise specified - TA = 25°C)
Symbol
VINDC
IINsd
Parameter
Min
8.0
-
Typ
Max
450
1
Units Conditions
Input DC supply voltage range
Shut-down mode supply current
Internally regulated voltage
Maximal pin VDD voltage
V
mA
V
DC input voltage
Pin PWM_D to GND, VIN = 8V
0.5
7.5
-
VDD
7.0
-
8.0
13.5
VIN = 8 – 450V, IDD(ext) = 0, pin GATE open
When an external voltage applied to pin VDD
VDDmax
V
VDD current available for external
IDD(ext)
-
-
1.0
mA
VIN = 8 – 100V
circuitry 1
UVLO
∆UVLO
VEN(lo)
VEN(hi)
REN
VDD undervoltage lockout threshold
VDD undervoltage lockout hysteresis
Pin PWM_D input low voltage
6.45
-
6.7
500
-
6.95
-
V
mV
V
VIN rising
VIN falling
-
1.0
-
VIN = 8 – 450V
VIN = 8 – 450V
VEN = 5V
Pin PWM_D input high voltage
2.4
50
-
V
Pin PWM_D pull-down resistance
100
150
kΩ
Current sense pull-in threshold
voltage
VCS(hi)
225
250
275
mV
@TA = -40°C to +85°C
VGATE(hi)
VGATE(lo)
GATE high output voltage
VDD-0.3
0
-
-
VDD
0.3
V
V
IOUT = 10mA
IOUT = -10mA
GATE low output voltage
20
80
25
100
30
120
kHz
kHz
R = 1.00MΩ
RTT = 226kΩ
fOSC
Oscillator frequency
DMAXhf
VLD
Maximum PWM duty cycle
-
0
-
-
100
250
280
%
mV
ns
FPWMhf = 25kHz, at GATE, CS to GND.
@TA = <85°C, VIN = 12V
Linear dimming pin voltage range
TBLANK
Current sense blanking interval
150
215
VCS = 0.55VLD, VLD = VDD
1 Also limited by package power dissipation limit, whichever is lower.
2
HV9910
Symbol Parameter
Min
Typ Max Units Conditions
VIN = 12V, VLD = 0.15,
tDELAY
Delay from CS trip to GATE lo
-
-
300
ns
VCS = 0 to 0.22V after TBLANK
tRISE
tFALL
GATE output rise time
GATE output fall time
-
-
30
30
50
50
ns
ns
CGATE = 500pF
CGATE = 500pF
Pinout
Pin
SOIC-16
SOIC-8
Description
VIN
CS
1
4
5
8
1
2
3
4
Input voltage 8V to 450V DC
Senses LED string current
Device ground
GND
GATE
Drives the gate of the external MOSFET
Low Frequency PWM Dimming pin, also Enable input. Internal
100kΩ pull-down to GND
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
LD
RT
13
14
7
8
Oscillator control. A resistor connected between this pin and
ground sets the PWM frequency.
No Connects (NC) are not internally connected and may be used for pass-thru PCB traces.
Block Diagram & Typical Applications
V
IN
V
IN
R
T
REG
7.5V
OSC
V
DD
V
DD
250mV
CM
CM
GATE
CS
S
R
Q
LD
PWM_D
100k
HV9910
GND
3
HV9910
Application Information
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.
AC/DC Off-Line Applications
The HV9910 is a low-cost off-line buck or 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 typical application circuit diagram of Figure 1.
Supply Current
A current of 1mA is needed to start the HV9910. As shown
in the block diagram on page 3, this current is internally
generated in the 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.
Setting Light Output
When the buck converter topology of Figure 2 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 is offered in a standard 8-pin SOIC package. It
is also available in a high voltage rated SO-16 package for
applications that require VIN greater than 250V.
TheHV9910includesaninternalhigh-voltagelinearregulator
that powers all internal circuits and can also serve as a bias
supply for low voltage external circuitry.
LED Driver Operation
Dimming
TheHV9910cancontrolallbasictypesofconverters, isolated
or non-isolated, operating in continuous or discontinuous
conductionmode.Whenthegatesignalenhancestheexternal
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 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.
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 example, a potentiometer connected between V and
ground can program the control voltage at the CDSD 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.
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 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
The PWM dimming scheme can be implemented by applying
an external PWM signal to the PWM_D pin. The PWM signal
4
HV9910
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.
Some of the typical waveforms illustrating the PWM dimming
method used with the application circuit on page 7 are given
below. CH shows the MOSFET Drain voltage, CH2 is the
PWM sign1al 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 RT pin:
FOSC = 25000/(RT [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 typical application circuit on page 7 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
Inductor Design
Referring to the typical application circuit on page 7 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.
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.
95% PWM Ratio at 500Hz Dimming
5
HV9910
Knowing the nominal rectified input voltage VIN = 120V*1.41
= 169V, the switching duty ratio can be determined, as:
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.
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:
=
Output Open Circuit Protection
TON = D/fOSC = 3.5 microsecond
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.
The required value of the inductor is given by:
L = (VIN - VLEDs) * TON /(0.3 * ILED) = 4.6mH
DC/DC Low Voltage Applications
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:
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
CMIN = ILED*VLEDs*0.06/VIN^2
CMIN = 22 µF, a value 22µF/250V can be used.
A passive PFC circuit at the input requires using two series limitation is related to the output current instability that may
connected capacitors at the place of calculated CMIN. Each of develop when the HV9910 buck converter operates at a
these identical capacitors should be rated for ½ of the input duty cycle greater than 0.5. This instability reveals itself as
voltage and have twice as much capacitance.
an oscillation of the output current at a sub-harmonic of the
switching frequency.
6
HV9910
Figure 1: Typical Application Circuit
1N4004 1N4004
68µF
160V
2A
250V
Coilcraft
BUSH-2820R5b
1N4004
BYV26B
280 kΩ
LEDs
VIN
RT
0.1µF
250V
AC Input
85 - 135VAC
0.1µF
250V
750μH
1.0μF
10V
VDD
1N4004
HV9910
2R
NTC
VN2224
0.2Ω
GATE
1N4004
1N4004
1N4004
220nF
400V
68µF
160V
0.1µF
250V
LD
1.0nF
250V
CS
Optional for PFC
GND
PWM_D
LED(s) - a string of HB LEDs, 16 diodes
Figure 2: HV9910 Buck driver for a simple 900mA HB LED (VIN = 8 - 30V)
VIN +1
C7
C6
10µF,
VIN = 8-30V
10µF,
35V
35V
D2
B140-13
HB LED
900mA at 4.5V
VIN -1
L2
1
2
U2
1
R11
267KΩ
220µH
6
7
5
8
RT
VDD
Q2
HV9910
4
2
LD
Gate
VN3205
C5
2.2µF,
10V
PWMD
CS
R10
0.27Ω
3
PWMD1
7
HV9910
16-Lead SOIC (NG) Package Outline
9.9 0.10
16
Notes:
Note 2
1. All dimensions in millimeters; angles in degrees
2. Pin 1 identifier must be located within the indicated area
3. Corner shape may differ from drawing
3.90 0.10
6.0 0.20
1
Top View
5O - 15O (4 PLCS)
0.25 - 0.50
0.17 - 0.25
45°
Note 3
1.75 MAX
O
0O-8
1.25MIN
0.10 - 0.25
1.27BSC
0.31 - 0.51
0.40 -1.27
End View
Side View
8-Lead SOIC (LG) Package Outline
4.90 0.10
8
6.00 0.20
Notes:
1. All dimensions in millimeters. Angles in degrees.
2. If the corner is not chamfered, then a Pin 1 identifier
must be located within the area indicated.
Note 2
3.90 0.10
1
5° - 15°
(4 PLCS)
0.25 - 0.50
Note 2
Top View
45°
0.17 - 0.25
1.25 MIN
1.75 MAX
0.10 - 0.25
0° - 8°
0.40 - 1.27
0.31 - 0.51
1.27BSC
End View
Side View
(The package drawings in this data sheet may not reflect the most current specifications. For the latest package outline
information go to http://www.supertex.com/packaging.html.)
Doc.# DSFP-HV9910
D021607
8
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