SP7616ER-L/TR [SIPEX]
High Accuracy 4-Channel Low Side LED Driver for CCFL Replacement; 高精度四通道低边LED驱动器，用于替代CCFL
| 型号： | SP7616ER-L/TR |
| 厂家： | 
SIPEX CORPORATION |
| 描述： | High Accuracy 4-Channel Low Side LED Driver for CCFL Replacement |
| 文件： | 总9页 (文件大小：572K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
High Accuracy 4-Channel Low Side
LED Driver for CCFL Replacement
FEATURES
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Wide 4.5V to 30V operating range
60mA LED current per channel
1.5% channel to channel current matching
Analog Dimming control
PWM operation up to 5kHz with 10% Duty Cycle
Low dropout: 150mV @ 20mA
Built-in Over Temperature Protection
Lead Free, RoHS Compliant Packaging:
Small 2X3mm DFN
Connect heat sink
pad to GND
DESCRIPTION
The SP7616 is a 30V 4-Channel linear low side LED driver. It is capable of powering up to four
LED strings of nine LEDs @ 60mA per string for a total of 36 LEDs with 1.5% typical current
matching between channels. The desired LED current can be adjusted with an external resistor,
and the precision string-to-string current matching ensures consistent color temperature across
the whole display. The device also features very low dropout voltage to maximize system
efficiency and avoid difficult thermal design constraints. Dimming can be achieved by feeding a
PWM signal to the PWM pin, or use an analog signal to control the ISET current, this allows
brightness control without unwanted color shifts. Fast LED current turn-on/off time allows up to 5
kHz PWM dimming frequencies with as low as 10% duty cycle, completely eliminating flicker. The
built-in thermal protection prevents damage to the device under fault conditions.
TYPICAL APPLICATION CIRCUIT
R
SET
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ABSOLUTE MAXIMUM RATINGS
These are stress ratings only and functional operation
of the device at these ratings or any other above those
indicated in the operation sections of the specifications
below is not implied. Exposure to absolute maximum
rating conditions for extended period of time may affect
reliability.
VIN……….…………………………………….…-0.3V to 32V
LED1, LED2, LED3, LED4 ……………..…... -0.3V to 32V
ISET, PWM …..…………………..………….. -0.3V to 6.0V
Storage Temperature..…………………… -65 °C to 150 °C
Junction Temperature.............................. -40°C to +150°C*
Lead Temperature (Soldering, 10 sec)....……………300°C
* Internally protected
ELECTRICAL SPECIFICATIONS
Unless otherwise specified: VIN = 4.5V - 30V, CIN = 1µF, -40°C < TA < 85°C, - 40°C <TJ< 125°C. Bold values apply over the full
operating temperature range.
PARAMETER
MIN
TYP
MAX
UNITS
CONDITIONS
Operating Input Voltage Range
4.5
30
V
Voltage at ISET is pulled to 3V;
IN 30V
Shutdown Supply Current
30
40
µA
V
No LED connected, VLED pins
are tied to GND. RSET=1Mꢀ
ILED = 30mA
Quiescent Supply Current
Quiescent Supply Current
Quiescent Supply Current
350
1
500
1.5
3
µA
mA
mA
1.5
ILED = 60mA
To reference channel (channel 2)
-40°C < TA < 85°C
LED Current Matching
-3
1.5
3
1
%
VLED = 0.5V to 25V , VIN = 28V,
RSET =50kΏ2
LED Current Line Regulation
0.5
%/V
Line Regulation
0.05
0.1
60
2
% / V
mA
µA
V
IN = 4.5V to 25V, VLED=0.5V 3
Maximum LED Current per channel
LED Leakage Current
Dropout Voltage
RSET = 15.38KΏ,
PWM pin LOW’ VLED 1V; VIN 5V
Note 4
0.2
950
150
0.3
V
Output/ISET Current Multiplication
Ratio
Thermal Shutdown Die Temperature
+/- 4 Percent -40°C < TA < 85°C
ILED = 0mA. LED current will self
recover when temperature drops
below the trip point, minus
thermal shut down hysteresis.
Driver is disabled
°C
°C
Thermal Shutdown Hysteresis
15
PWM Pin Logic LOW
PWM Pin Logic HIGH
PWM pin Hysteresis
ISET Voltage
0.8
5.5
V
V
mV
2.4
Driver is active
400
1.00
0.985
1.015
If ISET is pulled above this
threshold the device goes into full
shutdown
3
ISET Shutdown Threshold
V
ISET Shutdown Threshold Hysteresis
PWM Dimming Frequency Range
PWM Dimming Duty Cycle Range
0.3
V
kHz
%
0.1
10
5
90
Applied to PWM pin
Applied to PWM pin
VMOD from 5V to 0.0V, RSET =
50kꢀ
VMOD from 0.0V to 5V, RSET =
50kꢀ
Turn-on time from Shutdown
Turn-off time into Shutdown
100
300
20
µs
µs
Note
1. Reference channel ILED Variations from specified by RSET value
2. ILED Variations from specified by RSET value at VLED changing from 0.5 to 25V
3. ILED Variations from specified by RSET value at VIN changing from 4.5 to 25V
4. RSET = 31.6KΏ: Dropout voltage is measured as the VLED voltage where LED current drops 5% from nominal value
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PIN DESCRIPTION
PIN
NAME
DESCRIPTION
PIN #
Input voltage for the IC. Connect a 1uF decoupling
capacitor between this pin and ground.
V
IN
1
2
This pin must be held high to enable the output drivers. It can
be used for PWM dimming up to 5 kHz.
PWM
Connect resistor RSET from this pin to ground to set output
current. Pulling this pin above the shutdown threshold
stated in the Electrical Specifications puts the IC into
shutdown mode
3
4
I
SET
GND
Ground return for LED currents and circuitry of the SP7616
Connect an LED between each pin and VIN. Current value
is controlled by RSET. The current level through each pin is
internally matched within 3%. Connect unused channel (s)
to GND to save current consumption.
LED1-
LED4
5 - 8
BLOCK DIAGRAM
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TYPICAL PERFORMANCE CHARACTERISTICS
V
IN
V
IN
ILED 20mA/Div
ILED 20mA/Div
Typical Turn on Characteristics
Channel 1 VIN; Channel 4 ILED
Turn on Maximum VIN
Channel 1 VIN; Channel 4 ILED
PWM Signal
PWM Signal
VLED(Cathode Voltage)
VLED(Cathode Voltage)
LED current
20mA/Div
LEDcurrent
20mA/Div
PWM Function 1kHz 50% Duty Cycle
PWM Function 1 kHz 10% Duty Cycle
PWM Signal
PWM Signal
VLED (Cathode Voltage)
VLED (Cathode Voltage)
LED
current
LED current
20mA/Div
PWM Function 1 kHz 90% Duty Cycle
PWM Function 5 kHz 50% Duty Cycle
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TYPICAL PERFORMANCE CHARACTERISTICS
LED Current vs. LED voltage (cathode voltage)
IN tied to Anode of LED chain
V
Shutdown current vs. input voltage
Voltage on SET pin = 3V
I
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THEORY OF OPERATION
Introduction
VMOD is an adjustment voltage applied to the bottom
side of RSET, 950 is a typical current multiplication
ratio IMULT, and ILED is a required LED current in
mA/channel. Figure 1 shows the location of the
external VMOD source.
The SP7616 is a four-channel constant current
source LED driver with programmable output
current level. The design consists of a regulator
reference voltage source, current amplifier, and
output driver. The precision reference voltage
ensures good performance over voltage and
temperature. The four outputs are tightly coupled
allowing for excellent LED current matching.
Setting LED current
The LED current is set through the Iset resistor.
The SP7616 provides an internal reference voltage
that is set to 1V at the Iset Pin (Pin3). RSET is then
determined by using equation 1.
Figure 1
If adjustment voltage VMOD is not used, RSET resistor
should be connected to ground.
RSET = VISET *IMULT/ILED (kΩ),
Where
(1)
Shutdown using ISET pin
VISET is the internal reference (1V)
IMULT ISET Current Multiplication
Ratio
In normal operation, the voltage at ISET pin is
around 1V. To ensure fast turn on at low duty cycle
and high PWM frequency, only the output drivers
are switching in PWM mode. However, the whole
chip can be shutdown by pulling the voltage at ISET
up to 3V minimum.
ILED is the desired Led current.
In example 1: For a 20mA LED current, the current set
resistor should be
R
SET=1V*950/20mA (kΩ),
RSET=47.5Kꢀ
PWM Dimming
VCC pin Considerations
VIN of the SP7616 (Pin 1) needs to be connected to
the anode of the LED for proper operation
The LED dimming control is done through the PWM
pin. The acceptable frequency range of this signal
is 100Hz to 5kHz. The acceptable duty cycle range
of the signal is 10% to 90% at 1KHZ. When the
PWM pin is driven low, only the LED current
sources are disabled while the rest of the chip is
still enabled. .
Unused Channels and LED 2 Channel (pin 7)
LED 2 channel should never be grounded or left
unconnected it should always be used during
operation.
Other unused channels can be tied to the ground to
save on power consumption.
Analog dimming control
Shorted LEDs
Besides digital PWM control, the LED current can
be controlled continuously (from high to low LED
current) by raising the voltage at the bottom of RSET
from 0.0V to 1V maximum. RSET value may be
determined from equation 1. Equation 2 shows the
effect of using a VMOD in the circuit on the Led
current
If all LEDs on a string are shorted, the LED cathode
voltage will be VIN. It is still a working condition for
this device but it significantly increases the
dissipated power.
At 20mA LED current and VIN = 30V additional
power dissipated in the package is equal to 600mW
that will increase die temperature to 590C/W x 0.6W
= 35.40C, where 590C/W is 2x3 mm DFN package
thermal resistance. Assuming that all other
channels are working at VLED =1.5V the die
temperature will be approximately 410C above
ambient temperature and that decreases operating
temperature range. Also to protect the part if too
ILED = (1V – VMOD)*IMULT/RSET mA
Where
(2)
1V typical ISET pin voltage
IMULT ISET Current Multiplication
Ratio
ILED is the desired Led current.
VMOD is the adjustment voltage
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2007 Sipex Corporation
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THEORY OF OPERATION
Over-temperature protection
many LEDs are shorted, and the VLED voltage
The SP7616 offers Over-temperature protection.
When the die temperature rises above 1500C the
output drivers are shut off. The output current will
self recover when the temperature drops below the
trip point with the preset hysteresis of 150C. Thus a
part that shut off at 1500C will not try to restart
unless the die temperature is below 1350C
becomes to high, making the part dissipates too
much power, the over temperature protection will
shut the part off when the die temperature reaches
1500C. For further information refer to the over-
temperature protection section.
TYPICAL APPLICATION CIRCUITS
Figure 2
Typical Application: CCFL Replacement powered from 3 Li-ion batteries.
Figure 3
Using the SP7616 from a fixed source.
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PACKAGE: 2mmx3mm 8–Pin DFN
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ORDERING INFORMATION
Temperature
Range
Package
Type
Pack Type/
Quantity
Part Number
Lead Free
6 Pin TSOT
Lead Free
6 Pin TSOT
Tape & Reel /
2500
SP7616ER-L/TR
SP7616ER-L
-40°C to +85°C
-40°C to +85°C
Bulk
For further assistance:
Email:
WWW Support page:
Sipex Application Notes:
Sipexsupport@sipex.com
http://www.sipex.com/content.aspx?p=support
http://www.sipex.com/applicationNotes.aspx
Sipex Corporation
Solved by
Headquarters and
Sales Office
233 South Hillview Drive
Milpitas, CA95035
tel: (408) 934-7500
FAX: (408) 935-7600
TM
Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the application or use of any product
or circuit described herein; neither does it convey any license under its patent rights nor the rights of others.
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2007 Sipex Corporation
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