Off-Line, High Brightness LED Driver
Features
•
8V
DC
to 450V
DC
Input Voltage Range
•
>90% Efficiency
•
Drives Multiple LEDs in Series/Parallel
Combinations
•
Regulated LED Drive Current
•
Linear or PWM Brightness Control
•
Resistor-Programmable Oscillator Frequency
•
RoHS Compliant
MXHV9910
Description
The MXHV9910 is a low-cost, high-brightness (HB)
LED driver manufactured using Clare’s high-voltage
BCDMOS on SOI process. This driver has internal
circuitry that allows it to operate from a universal AC
line or from 8V
DC
to 450V
DC
. This highly versatile
input operating voltage enables this IC to be used in a
broad range of HB LED applications.
The driver features a fixed-frequency, peak-current
control method, which provides an ideal solution for
driving multiple LEDs in series and in parallel. In
addition, LED dimming can be implemented by
applying a small DC voltage to the LD pin, or by
applying a low-frequency digital PWM signal to the
PWMD pin.
The MXHV9910 is available in a standard 8-lead SOIC
package and a thermally enhanced 8-lead SOIC
package with an Exposed Thermal Pad (EP)
Applications
•
Flat-Panel Display RGB Backlighting
•
Signage and Decorative LED Lighting
•
DC/DC or AC/DC LED Driver Applications
Ordering Information
Part
Description
SOIC-8 (100/Tube)
SOIC-8 Tape & Reel (2000/Reel)
SOIC-8 EP (100/Tube)
With Exposed Thermal Pad
SOIC-8 EP Tape & Reel (2000/Reel)
With Exposed Thermal Pad
Pb
RoHS
2002/95/EC
e
3
MXHV9910B
MXHV9910BTR
MXHV9910BE
MXHV9910BETR
Block Diagram
V
DD
V
IN
6
1
Voltage
Reference
250mV
Voltage
Regulator
R
T
8
OSC
-
+
PWM
Control
4
GATE
LD
PWMD
GND
7
5
3
-
+
2
CS
DS-MXHV9910-R01
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1
MXHV9910
1
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.1 Package Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3 Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.4 Recommended Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.5 Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.6 Thermal Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2 LED Driver Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2.1 Input Voltage Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2.2 Current Sense Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2.3 Current Sense Blanking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2.4 Enable/Disable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2.5 Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2.6 Inductor Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2.7 Gate Output Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2.8 Linear Dimming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2.9 PWM Dimming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2.10 Combination Linear and PWM Dimming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Manufacturing Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1 Mechanical Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2 Packaging Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.1 Tape & Reel Information for both 8-Pin Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3 Soldering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4 Washing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
3
3
3
4
4
4
5
5
5
6
6
7
7
7
7
8
8
8
9
2
3
10
10
11
11
11
11
R01
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2
MXHV9910
1. Specifications
1.1 Package Pinout
1.2 Pin Description
Pin#
1
2
3
4
5
6
Name
V
IN
CS
GND
GATE
PWMD
V
DD
LD
R
T
Input voltage
Description
LED Current Sense input. Internal current
sense threshold is set at 250mV. The external
sense resistor sets the maximum LED current.
Device Ground
External MOSFET gate driver output
Low-frequency PWM dimming control input with
internal pull-down resistor.
Regulated supply voltage output. Requires a
storage capacitor to GND. Can be overdriven by
external voltage applied to V
DD
.
Linear Dimming. Apply a voltage less than
V
CS(high)
to dim the LED(s).
Resistor to GND sets the oscillator/primary
PWM frequency.
Electrical and thermal conductive pad on the
bottom of the MXHV9910BE. Connect this pad
to ground, and provide sufficient thermal
coupling to remove heat from the package.
V
IN
CS
GND
GATE
1
2
3
4
8
7
6
5
R
T
LD
V
DD
PWMD
7
8
EP
-
1.3 Absolute Maximum Ratings
Parameter
Input Voltage to GND
Inputs & Outputs Voltage to GND
V
DD
, Externally Applied
Power Dissipation
SOIC-8 With Thermal Tab
SOIC-8 W/O Thermal Tab
Maximum Junction Temperature
Operating Temperature
Junction Temperature (Operating)
Storage Temperature
P
D
T
Jmax
T
A
T
J
T
STG
2.5
0.975
150
-40 to +85
-40 to +150
-55 to +150
W
W
°C
°C
°C
°C
Symbol
V
IN
CS, LD, PWMD, GATE
V
DD.EXT
Maximum
-0.5 to +460
-0.3 to V
DD
+0.3
15
Unit
V
V
V
Electrical absolute maximum ratings are at 25°C.
Absolute maximum ratings are stress ratings. Stresses in
excess of these ratings can cause permanent damage to
the device. Functional operation of the device at conditions
beyond those indicated in the operational sections of this
data sheet is not implied.
R01
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3
MXHV9910
1.4 Recommended Operating Conditions
Parameter
Input Voltage Range
PWMD Frequency
Operating Temperature
Symbol
V
IN
f
PWMD
T
A
Minimum
8
-
-40
Nominal
-
500
-
Maximum
450
-
+85
Unit
V
DC
Hz
°C
1.5 Electrical Characteristics
Unless otherwise specified, all electrical specifications are provided for T
A
=25°C.
Parameter
Input
Input DC Voltage Range
Shut-Down Mode Supply Current
Maximum Voltage to V
DD
Pin
Regulator
Internal Voltage Regulator
V
DD
Current Available
for External Circuitry
V
DD
Load Regulation
PWM Dimming
PWMD Input Low Voltage
PWMD Input High Voltage
PWMD Pull-Down Resistance
Current Sense Comparator
Current Sense (CS) Input Current
CS Low
CS High
Current Sense Threshold Voltage
Current Sense Blanking Interval
Delay from CS Trip to Gate Low
Oscillator
Oscillator Frequency (Gate Driver)
Gate Driver
Gate High Output Voltage
Gate Low Output Voltage
Gate Output Rise Time
Gate Output Fall Time
Conditions
DC Input Voltage
PWMD to GND, V
IN
=15 to 450V
External Voltage applied to V
DD
Pin
V
IN
=15V to 450V,
I
DD(ext)
=0,
GATE Output=Open
-
V
IN
=15V, I
L
=1mA
V
IN
=8V to 450V
V
IN
=8V to 450V
V
IN
=12V, V
PWMD
=V
DD
Symbol
V
IN
I
INSD
V
DDmax
Minimum
8
-
-
Typical
-
0.3
-
Maximum
450
0.6
12
Unit
V
DC
mA
V
V
DD
I
DD(ext)
ΔV
DD
V
EN
(low)
V
EN
(high)
R
EN
7.2
-
-
-
2.4
70
7.8
-
-
-
-
115
8.4
2
200
0.5
-
150
V
DC
mA
mV
V
kΩ
CS=0V
CS=V
DD
-40°C < T
A
< 85°C
R
T
=400kΩ
R
T
=400kΩ
R
T
=400kΩ
I
OUT
= -10mA
I
OUT
=10mA
C
GATE
=500pF
C
GATE
=500pF
I
IL
I
IH
V
CS(high)
t
BLANK
t
DELAY
f
S
V
GATE
(hi)
V
GATE
(lo)
t
RISE
t
FALL
-
-
200
-
-
51
V
DD
-0.3
-
-
-
-45
0
-
400
300
64
-
0.03
16
7
-90
±15
280
-
-
77
-
0.3
-
-
μA
mV
ns
ns
kHz
V
ns
1.6 Thermal Characteristics
Parameter
Thermal Resistance,
Junction-to-Ambient
1
Package
SOIC-8 With Thermal Pad (BE)
1
SOIC-8 W/O Thermal Pad (B)
Symbol
R
θJA
Minimum
-
-
Typical
50
128
Maximum
-
-
Unit
°C/W
Use of a four-layer PCB can improve thermal dissipation (reference EIA/JEDEC JESD51-5).
4
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R01
MXHV9910
2. Functional Description
Figure 1 Typical Application Circuit
8-450V
V
DD
6
1
V
DD
V
IN
Voltage
Reference
250mV
Voltage
Regulator
8
R
T
OSC
-
+
PWM
Control
GATE
4
7
5
3
LD
-
+
PWMD
GND
CS
2
R
SENSE
2.1 Overview
The MXHV9910 is a high-efficiency, low cost, off-line
LED driver designed using Clare's state of the art
BCDMOS on SOI process. The driver can operate
from a DC supply voltage between 8 to 450V
DC
. The
versatile input supply voltage range enables this driver
to be used in a broad range of applications such as flat
panel display RGB backlighting, signage, decorative
LED lighting, and incandescent lamp replacement.
The MXHV9910 IC is configured in a buck converter
topology, which is a perfect choice for off-line and DC
applications driving multiple LEDs in series or parallel.
This method provides excellent efficiency and enables
a buck switcher design using a minimum number of
external components. An external current sense
resistor sets the peak current to the LED string. In
addition, LED dimming can be implemented by either
applying a DC control voltage to the LD pin, or by
applying a low frequency, pulse-width modulated
digital signal to the PWMD pin (typically 500 Hz).
located at the CS pin. When the rising voltage at the
current sense, CS, pin exceeds V
CS(high)
, the internally
set threshold, the gate drive signal goes low and turns
off the external power MOSFET. Turning the power
MOSFET off causes the inductor current to decay until
the next rising edge of the clock, and the process
repeats.
The peak current threshold is set by comparing the
voltage developed across the R
SENSE
resistor to the
internal threshold, V
CS(high)
. This default threshold can
be overridden externally by applying a voltage less
than V
CS(high)
to the LD pin. The lower of these two
thresholds limits the peak current in the inductor
A soft-start function can be implemented by slowly
ramping up the DC voltage at the LD pin from 0mV to
a level greater than 250mV.
Figure 2
shows a typical
recommended soft-start circuit design.
Figure 2 Soft-Start RC Network
MXHV9910
51kΩ
2.2 LED Driver Theory of Operation
The gate driver pulse width mode (PWM) control
circuit is enabled by connecting the PWMD pin to the
V
DD
pin. When enabled, the rising edge of each
internal clock turns on the gate driver and the external
power MOSFET, causing the inductor current to ramp
up the voltage across the current sense resistor
R01
V
IN
CS
GND
GATE
R
T
LD
V
DD
PWMD
2kΩ
0.1μF
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