Compact 2-3-4-Ch LED Drivers with Phase Shift Control
ISL97682, ISL97683, ISL97684
The ISL97682, ISL97683, ISL97684 are Intersil’s highly
integrated 2-3-4-channels LED drivers that are suitable for
medium size TFT-LCD backlights. These parts can drive multiple
channels of LEDs from inputs as low as 4V to outputs of up to
45V. They can also operate from inputs as low as 3V to outputs of
up to 26.5V in bootstrap configuration (see Figure 26 for 3V
operation).
The ISL97682, ISL97683, ISL97684 feature optional channels
phase shift control. This feature is used to minimize the input,
output ripple characteristics and load transient, which help
eliminate or reduce the video and audio noise interference from
the backlight driver operation.
The ISL97682, ISL97683, ISL97684 offer 8-bit PWM dimming for
systems that need frequency tuning flexibility. With the unique
adaptive boost switching architecture, the ISL97682, ISL97683,
ISL97684 also offer Direct PWM dimming with output, which
follows input and achieves linearity as low as 0.009% at 200Hz
or 1.35% at 30kHz.
The drivers incorporate dynamic headroom control that monitors
the highest LED forward voltage string and uses its feedback signal
for the minimum output regulation. The ISL97682, ISL97683,
ISL97684 incorporates extensive fault protection functions including
string open and short circuit detections, OVP, and OTP. The switching
frequency can be selected at either 600kHz or 1.0MHz in PFM or
PWM mode. These parts are available in the thin and compact
16 Ld 3mmx3mm TQFN package and operate in ambient
temperature from -40°C to +85°C.
Features
• ISL97682 - 2 x 100mA Channels
• ISL97683 - 3 x 50mA Channels
• ISL97684 - 4 x 50mA Channels
• Input Voltage 4.0V~26.5V with Max V
OUT
of 45V
• Input Voltage 3.0V (see Figure 26)~24V with Max V
OUT
of 26.5V
• PWM Dimming Linearity
- PWM Dimming with Adjustable Dimming Frequency with
Duty Cycle Linear from 0.4% to 100% <30kHz
- Direct PWM Dimming with Duty Cycle Linear from 0.009%
to 100% at 200Hz
• Current Matching of 0.7% typical from 1%~100% Dimming
• Selectable 600kHz or 1MHz Switching Frequency in PWM/PFM
Mode
• Dynamic Headroom Control
• Fault Protection
- String Open/Short Circuit Protections, OVP, OTP
• Thin and Compact TQFN-16 3mmx3mm Package
Applications
• Tablet to Notebook PC Displays LED Backlighting
• PMP LED Backlighting
V
IN
= 4~26.5V
Ci
10µF
7 VIN
0.1µF
1µF
6 EN
5 PWMI
3 RSET
11 VDC
L1
10µH
D1
45V, 4 x 50mA*
Co
4.7µF
V
IN
= 4~26.5V
Ci
10µF
7 VIN
0.1µF
11 VDC
L1
10µH
D1
45V, 4 x 50mA*
Co
4.7µF
LX 9
ISL97684
OVP 12
LX 9
ISL97684
OVP 12
1µF
6 EN
5 PWMI
PGND 10
CH1 13
CH2 14
CH3 15
CH4 16
3 RSET
8 FPWM/DIRECTPWM
4 FSW
2 COMP
PGND 10
CH1 13
CH2 14
CH3 15
CH4 16
8 FPWM/DIRECTPWM
4 FSW
2 COMP
1 AGND
*V
IN
> = 9V AND WITH
GOOD LEDS MATCHING
1 AGND
*V
IN
>=9V AND WITH
GOOD LEDS MATCHING
FIGURE 1A. DIRECT PWM DIMMING
FIGURE 1B. PWM DIMMING WITH DIMMING FREQUENCY
ADJUSTMENT USING R
FPWM
FIGURE 1. ISL97684 TYPICAL APPLICATION DIAGRAMS
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774
|
Copyright Intersil Americas Inc. 2011. All Rights Reserved
Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries.
All other trademarks mentioned are the property of their respective owners.
March 11, 2011
FN7689.0
1
ISL97682, ISL97683, ISL97684
Block Diagram
V
IN
= 4~26.5V
OPTIONAL FUSE
10µH/1.5A
LX
VIN
EN
VDC
OSC &
RAMP
COMP
FSW
FSW
DETECT
PHASE
SELECT
OUTPUT = 45V, 4 X 50mA*
4.7µF/50V
REG
INTERNAL
BIAS
ISL97684
O/P SHORT
FET
DRIVER
OVP
OVP
Σ
=
0
♦∏
IMAX
ILIMIT
LOGIC
PGND
PE
OPEN CKT, SHORT CKT DETECTS
HIGHEST
VF
STRING
DETECT
+
-
COMP
GM
AMP
8-BIT
DAC
DYNAMIC
HEADROOM
CONTROL
CH1
CH4
VSET
+
-
1
RSET
REF
OVP
REF
VSC
REF
GEN
TEMP
SENSOR
PHASE SHIFT
& PWM
CONTROLLER
AGND
PHASE SELECT
PWMI
FPWM/
DIRECTPWM
8-BIT
DIGITIZER
DIRECTPWM
DETECT
*V
IN
>= 9V AND WITH
GOOD LEDS MATCHING
4
+
-
FIGURE 2. ISL97684 BLOCK DIAGRAM
Ordering Information
PART NUMBER
(Notes 1, 2, 3)
ISL97682IRTZ
ISL97683IRTZ
ISL97684IRTZ
ISL97682IRTZ-EVALZ
ISL97683IRTZ-EVAL
ISL97684IRTZ-EVALZ
NOTES:
1. Add “-T*” 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
ISL97682, ISL97683, ISL97684.
For more information on MSL please
see techbrief
TB363.
PART MARKING
7682
7683
7684
Evaluation Board
Evaluation Board
Evaluation Board
TEMP RANGE
(°C)
-40 to +85
-40 to +85
-40 to +85
PACKAGE
(Pb-free)
16 LD 3x3 TQFN
16 LD 3x3 TQFN
16 LD 3x3 TQFN
PKG.
DWG. #
L16.3x3D
L16.3x3D
L16.3x3D
2
FN7689.0
March 11, 2011
ISL97682, ISL97683, ISL97684
Pin Configurations
ISL97682
(16 LD TQFN)
TOP VIEW
CH2
CH1
NC
NC
ISL97683
(16 LD TQFN)
TOP VIEW
CH3
CH2
14
CH1
13
12 OVP
11 VDC
10 PGND
9
5
PWMI
6
EN
7
VIN
8
FPWM_DIRECTPWM
LX
NC
16
12 OVP
11 VDC
10 PGND
9
LX
AGND 1
COMP 2
RSET 3
FSW
4
16
AGND 1
COMP 2
RSET 3
FSW 4
5
PWMI
15
14
13
15
6
EN
7
VIN
8
FPWM_DIRECTPWM
ISL97684
(16 LD TQFN)
TOP VIEW
CH4
CH3
CH2
14
CH1
13
12 OVP
11 VDC
10 PGND
9
5
PWMI
6
EN
7
VIN
8
FPWM_DIRECTPWM
LX
16
AGND 1
COMP 2
RSET 3
FSW 4
15
3
FN7689.0
March 11, 2011
ISL97682, ISL97683, ISL97684
Pin Descriptions
PIN
1
2
3
4
ISL97682
AGND
COMP
RSET
FSW
ISL97683
AGND
COMP
RSET
FSW
ISL97684
AGND
COMP
RSET
FSW
Analog Ground for precision circuits
External Compensation Pin
Resistor connection for setting LED current, (see Equation 2 for calculating the ILEDpeak)
FSW = 0 ~ 0.25 * VDC, Boost Switching Frequency = 600kHz with phase shift and PFM mode enabled.
FSW = 0.25 * VDC ~ 0.5 * VDC, Boost Switching Frequency = 600kHz with phase shift and PWM mode
enabled.
FSW = 0.5 * VDC ~ 0.75 * VDC, Boost Switching Frequency = 1MHz with phase shift and PWM mode
enabled.
FSW = 0.75 * VDC ~ VDC, Boost Switching Frequency = 1MHz with phase shift and PFM mode enabled.
PWM brightness control pin.
Enable, can be tied directly to VIN if the system lacks of I/O
LED and Driver Supply Voltage. LED supply and Driver supply can be separated if high voltage application
is needed and dual supplies are available
DESCRIPTION
5
6
7
8
PWMI
EN
VIN
PWMI
EN
VIN
PWMI
EN
VIN
FPWM/
FPWM/
FPWM/
External PWM dimming with frequency modulation or Direct PWM dimming without frequency
DirectPWM DirectPWM DirectPWM modulation.
With a resistor connected to ground, the dimming frequency will be set by the Setting Resistor.
When this pin is floating, the part enters Direct PWM mode such that the dimming follows the input PWM
signal without frequency modulation.
LX
PGND
VDC
OVP
CH1
NC
CH2
NC
LX
PGND
VDC
OVP
CH1
CH2
CH3
NC
LX
PGND
VDC
OVP
CH1
CH2
CH3
CH4
Input to boost switch
Power ground (LX, C
IN
, and C
OUT
Power return)
De-couple capacitor for internally generated 5V supply
Overvoltage protection input
Input 1 to current source, CH, and monitoring
Input 2 to current source, CH, and monitoring (ISL97682 is No Connect)
Input 3 to current source, CH, and monitoring
Input 4 to current source, CH, and monitoring (ISL97682, ISL97683 are No Connect)
9
10
11
12
13
14
15
16
4
FN7689.0
March 11, 2011
ISL97682, ISL97683, ISL97684
Absolute Maximum Ratings
VIN, EN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 28V
VDC, PWMI, FPWM/DirectPWM, FSW, RSET, COMP, OVP . . . -0.3V to 5.5V
CH1 to CH4, LX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 45V
PGND, AGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +0.3V
Above voltage ratings are all with respect to AGND pin
Thermal Information
Thermal Resistance (Typical)
θ
JA
(°C/W)
θ
JC
(°C/W)
16 LD TQFN (Notes 4, 5) . . . . . . . . . . . . . . .
51
4.6
Thermal Characterization (Typical)
PSI
JT
(°C/W)
16 Ld TQFN (Note 6). . . . . . . . . . . . . . . . . . . . . . . . . . . . .
0.11
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
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.
6. PSI
JT
is the PSI junction-to-top thermal characterization parameter. 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.
Electrical Specifications
5.
All specifications below are characterized at T
A
= -40°C to +85°C; V
IN
= 12V, EN = 5V, R
SET
= 20kΩ,
unless otherwise noted. Boldface limits apply over the operating temperature range, -40°C to +85°C.
PARAMETER
DESCRIPTION
CONDITION
MIN
(Note 7)
TYP
MAX
(Note 7)
UNIT
GENERAL
V
IN
I
VIN
IVIN_STBY
V
OUT
V
UVLO
V
UVLO_HYS
Backlight Supply Voltage, (Note 8)
VIN Active Current
VIN Shutdown Current
Output Voltage
Undervoltage Lockout Threshold
Undervoltage Lockout Hysteresis
T
A
= +25°C
EN = 3.3V
EN = 0V,
T
A
= 25°C
4.0V < V
IN
≤
26.5V
2.2
100
4.0
5
5
45
2.5
26.5
V
mA
µA
V
V
mV
LINEAR REGULATOR
V
DC
V
LDO
EN
Low
EN
Hi
t
EN(Low)
SS
SW
ILimit
r
DS(ON)
Eff_peak
LDO Output Voltage
VDC LDO Dropout Voltage
Guaranteed Range for EN Input Low Voltage
Guaranteed Range for EN Input High Voltage
EN low time before shut-down
1.5
29.5
V
IN
> 6V
V
IN
= 5V, I
VDC
= 20mA
4.6
4.8
30
5
200
0.5
V
mV
V
V
ms
BOOST SWITCHING REGULATOR
Soft-start
Boost FET Current Limit
Internal Boost Switch ON-Resistance
Peak Efficiency
V
IN
= 24V, 48 LEDs, 30mA
each, L = 10µH with DCR
≤100mΩ,
T
A
= +25°C
V
IN
= 12V, 48 LEDs, 30mA
each, L = 10µH with DCR
≤
100mΩ, T
A
= +25°C
D
MAX
Boost Maximum Duty Cycle
V
FSW
< 2.4V (F
SW
= 600kHz)
V
FSW
> 2.4V
(F
SW
=1.0MHz)
92
85
100% LED Duty Cycle
1.4
7
1.8
500
90.1
2.3
ms
A
mΩ
%
87
%
%
%
5
FN7689.0
March 11, 2011
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