6-Channel LED Driver
ISL97672
The ISL97672 is an integrated power LED driver that
controls 6 channels of LED current for LCD backlight
applications. The ISL97672 is capable of driving up to
78 LEDs from 4.5V to 26V or 48 LEDs from a boost
supply of 2.7V to 26V and a separate 5V bias supply on
the VIN pin.
The ISL97672 compensates for non-uniformity of the
forward voltage drops in the LED strings with its 6 voltage
controlled-current source channels. Its headroom control
monitors the highest LED forward voltage string for output
regulation, to minimize the voltage headroom and power
loss in a typical multi-string operation.
The ISL97672 allows direct PWM mode by following the
external signal from 0Hz to 30KHz at 0.4% to 100% duty
cycle and maintaining a typical ±0.7% current matching
between channels.
The ISL97672 features a separate EN pin and extensive
protection functions that flag whenever a fault occurs.
The protections include string open and short circuit
detections, OVP, OTP, thermal shutdown and an optional
input overcurrent protection with fault disconnect switch.
ISL97672
Features
• 6 Channels
• 4.5V to 26.5V Input
• 45V Output Max
• Up to 40mA LED Current per channel
• Direct PWM Dimming without Phase Shift
• PWM Dimming Linearity 0.4%~100% <30kHz
• Adjustable 200kHz to 1.4MHz Switching Frequency
• Dynamic Headroom Control
• Protections with Flag Indication
- String Open/Short Circuit, V
OUT
Short Circuit,
Overvoltage and Over-Temperature Protections
- Optional Master Fault Protection
• Current Matching ±0.7%
• 20 Ld 4mmx3mm QFN Package
Applications*
(see page 16)
• Notebook Displays LED Backlighting
• LCD Monitor LED Backlighting
• Automotive Displays LED Backlighting
• Automotive or Traffic Lighting
Typical Application Circuit
V
IN
= 4.5V~26.5V
V
OUT
= 45V*, 40mA PER STRING
ISL97672
1 FAULT
2 VIN
4 VDC
18 COMP
6 /FLAG
CH0 10
CH1 11
5 PWM
3
EN
CH2 12
CH3 13
CH4 14
CH5 15
LX 20
OVP 16
PGND 19
17 RSET
8
9
FSW
AGND
* V
IN
> 12V
FIGURE 1. ISL97672 TYPICAL APPLICATION DIAGRAM
June 24, 2010
FN7632.0
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774
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Copyright Intersil Americas Inc. 2010. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
ISL97672
Block Diagram
VIN = 4.5V~26V
(Optional Q1)
VIN
EN
VDC
FAULT
Bias
Fault
Flag
45V*,
40mA
per string
25mA
78 (6x13) LEDs
10uH/3A
LX
4.7uF/50V
REG
OSC &
RAMP
Comp
O/P Short
OVP
Boost SW
OVP
fsw
/FLAG
Fault
Flag
Σ
=0
Imax
ILIMIT
Logic
FET
Driver
PGND
p
e
Fault/Status Control
COMP
GM
AMP
VSET
Open Ckt, Short Ckt
Detects
Highest VF
String Detect
+
-
CH0
CH1
CH5
0
Temp
Sensor
Fault
Flag
RSET
+
-
REF
GEN
REF_VSC
PWM0
1
REF_OVP
GND
PWM1
+
-
PWM
PWM
GENERATOR
PWM5
V
Vin
>
6V
*
IN
>
12V
+
-
5
ISL97672
FIGURE 2. ISL97672 BLOCK DIAGRAM
2
FN7632.0
June 24, 2010
ISL97672
Ordering Information
PART
NUMBER
(Notes 1, 2)
ISL97672IRZ
PART
MARKING
97672
PACKAGE
(Pb-Free)
20 Ld 4x3 QFN
PKG.
DWG. #
L20.3x4
Pin Configuration
ISL97672
(20 LD 4X3 QFN)
TOP VIEW
COMP
18
PGND
RSET
17
16 OVP
15 CH5
14 CH4
13 CH3
12 CH2
11
CH1
7
NC
8
FSW
9
AGND
10
CH0
LX
20
FAULT
VIN
EN
VDC
PWM
/FLAG
1
2
3
4
5
6
ISL97672IRZ-EVAL Evaluation Board
NOTES:
1. Add “-T” or “-TK” suffix for tape and reel. Please refer to
TB347
for details on reel specifications.
2. These Intersil Pb-free plastic packaged products employ
special Pb-free material sets, molding compounds/die
attach materials, and 100% matte tin plate plus anneal
(e3 termination finish, which is RoHS compliant and
compatible with both SnPb and Pb-free soldering
operations). Intersil Pb-free products are MSL classified at
Pb-free peak reflow temperatures that meet or exceed the
Pb-free requirements of IPC/JEDEC J STD-020.
3. For Moisture Sensitivity Level (MSL), please see device
information page for
ISL97672.
For more information on
MSL please see techbrief
TB363.
19
Pin Descriptions
PIN NAME
FAULT
VIN
EN
VDC
PWM
/FLAG
NC
FSW
AGND
CH0
CH1
CH2
CH3
CH4
CH5
OVP
RSET
COMP
PGND
LX
PIN #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
TYPE
O
S
I
S
I
O
I
I
S
I
I
I
I
I
I
I
I
O
S
O
(I = Input, O = Output, S = Supply)
DESCRIPTION
Fault disconnect switch
Input voltage for the device and LED power
The device needs 4ms for initial power-up Enable. It will be disabled if it is not biased for longer
than 28ms.
De-couple capacitor for internally generated supply rail.
PWM brightness control pin.
/Flag = 0 for any fault conditions. /Flag =1 for normal condition. Open drain that needs pull up.
No Connect
Boost switching frequency set pin by connecting a resistor. See the “Switching Frequency” section
for resistor calculation
Analog Ground for precision circuits
Input 0 to current source, FB, and monitoring
Input 1 to current source, FB, and monitoring
Input 2 to current source, FB, and monitoring
Input 3 to current source, FB, and monitoring
Input 4 to current source, FB, and monitoring
Input 5 to current source, FB, and monitoring
Overvoltage protection input
Resistor connection for setting LED current, (see Equation 1 for calculating the ILEDpeak)
Boost compensation pin
Power ground (LX Power return)
Input to boost switch
3
FN7632.0
June 24, 2010
ISL97672
Absolute Maximum Ratings
(T
A
= +25°C)
VIN, EN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 28V
FAULT . . . . . . . . . . . . . . . . . . . . . VIN - 8.5V to VIN + 0.3V
VDC, COMP, RSET, PWM, OVP, /FLAG, FSW . . . -0.3V to 5.5V
CH0 - CH5, LX . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 45V
PGND, AGND . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +0.3V
Above voltage ratings are all with respect to AGND pin
ESD Rating
Human Body Model (Tested per JESD22-A114E) . . . . . 3kV
Machine Model (Tested per JESD22-A115-A) . . . . . . . 300V
Charged Device Model . . . . . . . . . . . . . . . . . . . . . . . 1kV
Thermal Information
Thermal Resistance (Typical)
20 Ld QFN Package (Notes 4, 5, 7) .
Thermal Characterization (Typical)
θ
JA
(°C/W)
θ
JC
(°C/W)
40
2.5
PSI
JT
(°C/W)
20 Ld QFN Package (Note 6) . . . . . . . . . . . .
1
Maximum Continuous Junction Temperature . . . . . . +125°C
Storage Temperature . . . . . . . . . . . . . . . -65°C to +150°C
Pb-Free Reflow Profile . . . . . . . . . . . . . . . . . .see link below
http://www.intersil.com/pbfree/Pb-FreeReflow.asp
Operating Conditions
Temperature Range . . . . . . . . . . . . . . . . . . -40°C to +85°C
IMPORTANT NOTE: All parameters having Min/Max specifications are guaranteed. Typical values are for information purposes only. Unless
otherwise noted, all tests are at the specified temperature and are pulsed tests, therefore: T
J
= T
C
= T
A
CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact
product reliability and result in failures not covered by warranty.
NOTES:
4.
θ
JA
is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach”
features. See Tech Brief TB379.
5. For
θ
JC
, the “case temp” location is the center of the exposed metal pad on the package underside assumed under ideal case
temperature.
6. PSI
JT
is the junction-to-top thermal resistance. If the package top temperature can be measured, with this rating then the die
junction temperature can be estimated more accurately than the
θ
JC
and
θ
JC
thermal resistance ratings.
7. Refer to JESD51-7 high effective thermal conductivity board layout for proper via and plane designs.
Electrical Specifications
All specifications below are tested at T
A
= 25°C; V
IN
= 12V, EN = 5V, R
SET
= 20.1kΩ, unless
otherwise noted.
Boldface limits apply over the operating temperature range,
-40°C to +85°C.
CONDITION
MIN
(Note 8)
TYP
MAX
(Note 8) UNIT
PARAMETER
GENERAL
VIN (Note 9)
IVIN_STBY
V
OUT
DESCRIPTION
Backlight Supply Voltage
VIN Shutdown Current
Output Voltage
T
C
= <+60°C
T
A
= +25°C
4.5
26.5
10
V
µA
V
V
V
V
mV
4.5V < V
IN
≤
26V,
F
SW
= 600kHz
8.55V < V
IN
≤
26V,
F
SW
= 1.2MHz
4.5V < V
IN
≤
8.55V,
F
SW
= 1.2MHz
45
45
V
IN
/0.19
2.6
275
3.3
Vuvlo
Vuvlo_hys
Undervoltage Lock-out Threshold
Undervoltage Lock-out Hysteresis
ENABLE AND PWM GENERATOR
VIL
VIH
FPWM
t
ON
Guaranteed Range for PWM Input Low
Voltage
Guaranteed Range for PWM Input High
Voltage
PWM Input Frequency Range
Minimum On Time
1.5
200
250
0.8
VDD
30,000
350
V
V
Hz
ns
4
FN7632.0
June 24, 2010
ISL97672
Electrical Specifications
All specifications below are tested at T
A
= 25°C; V
IN
= 12V, EN = 5V, R
SET
= 20.1kΩ, unless
otherwise noted.
Boldface limits apply over the operating temperature range,
-40°C to +85°C. (Continued)
CONDITION
MIN
(Note 8)
TYP
MAX
(Note 8) UNIT
PARAMETER
REGULATOR
VDC
IVDC_STBY
IVDC
VLDO
ENLow
ENHi
t
ENLow
BOOST
SWILimit
r
DS(ON)
SS
Eff_peak
DESCRIPTION
LDO Output Voltage
Standby Current
Active Current
VDC LDO Droop Voltage
Guaranteed Range for EN Input Low
Voltage
Guaranteed Range for EN Input High
Voltage
EN low time before shut-down
V
IN
> 6V
EN = 0V
EN = 5V
V
IN
> 5.5V, 20mA
4.55
4.8
5
5
V
µA
mA
5
20
200
0.5
1.8
30.5
mV
V
V
ms
Boost FET Current Limit
Internal Boost Switch ON-Resistance
Soft-start
Peak Efficiency
T
A
= +25°C
100% LED Duty Cycle
V
IN
= 12V, 72 LEDs, 20mA
each, L = 10µH with DCR
101mΩ, T
A
= +25°C
V
IN
= 12V, 60 LEDs, 20mA
each, L = 10µH with DCR
101mΩ, T
A
= +25°C
1.5
2.0
235
7
92.9
2.7
300
A
mΩ
ms
%
90.8
%
ΔI
OUT
/ΔV
IN
Dmax
Line Regulation
Boost Maximum Duty Cycle
FSW = 600kHz
FSW = 1.2MHz
90
81
0.1
%
%
%
9.5
17
%
%
kHz
MHz
µA
Dmin
Boost Minimum Duty Cycle
FSW = 600kHz
FSW = 1.2MHz
f
S
f
S
I
LX_leakage
Minimum Switching Frequency
Maximum Switching Frequency
LX Leakage Current
RFSW = 200kΩ
RFSW = 33kΩ
LX = 45V, EN = 0
175
1.312
200
1.50
235
1.69
10
CURRENT SOURCES
I
MATCH
I
ACC
V
headroom
V
RSET
I
LEDmax
Channel-to-Channel Current Matching
Current Accuracy
Dominant Channel Current Source
Headroom at IIN Pin
Voltage at RSET Pin
Maximum LED Current per Channel
I
LED
= 20mA
T
A
= +25°C
R
SET
= 20.1kΩ
V
IN
= 12V, V
OUT
= 45V,
Fsw = 1.2MHz,
T
A
= +25°C
1.2
R
SET
=20.1kΩ
(I
OUT
= 20mA)
-1.5
500
1.22
40
1.24
±0.7
±1.0
+1.5
%
%
mV
mV
mA
FAULT DETECTION
VSC
Temp_shtdwn
Temp_Hyst
Short Circuit Threshold
Temperature Shutdown Threshold
Temperature Shutdown Hysteresis
PWM Dimming = 100%
5.2
5.85
150
23
6.6
V
°C
°C
5
FN7632.0
June 24, 2010
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