FAN5610 [FAIRCHILD]
LED Driver for White, Blue or any Color LED; LED驱动器为白色，蓝色或任何颜色的LED
| 型号： | FAN5610 |
| 厂家： | 
FAIRCHILD SEMICONDUCTOR |
| 描述： | LED Driver for White, Blue or any Color LED |
| 文件： | 总10页 (文件大小：107K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
www.fairchildsemi.com
FAN5610
LED Driver for White, Blue or any Color LED
Features
Description
• LED Driver for 4 Parallel-connected LEDs
• Low Voltage Drop (<350mV) to Support Direct Li-ion
Applications with Low VF LEDs
• Independent Control Loop for Each LED
• Regulated, Matched Constant Current in LEDs
• No External Components
• No EMI, No Switching Noise
• Built-in DAC for Digital and PWM Brightness Control
• Up to 91% Maximum Efficiency
The FAN5610 generates matched current source drives for a
maximum of four LEDs. Since each LED current source has
its own self-regulating loop, precise current matching is
maintained even if there is a substantial forward voltage
spread among the LEDs. LED pre-selection therefore is not
required. In order to minimize voltage drop, and maximize
efficiency, the value of the internal current sense resistors
connected in series with the LEDs is very low (10Ω). This is
an important consideration for direct DC-driven white LEDs
in battery-powered systems.
• Up to 84mA (21mA/LED) Bias Current
• 2.7V to 5.5V Input Voltage Range
• ICC < 1µA in Shutdown Mode
• 3mmX3mm MLP-8 Package
The LEDs’ current can be set to 0mA (OFF Mode), 7mA,
14mA, and 21mA with a built-in two-bit digital-to-analog
converter. Customized current settings can also be used.
When the control bits are set to zero, the internal circuitry is
disabled and the quiescent current drops below 1µA.
Applications
Both digital input lines (A, B) can be pulse-width-modulated
(PWM). Using PWM, any value of average LED current can
be obtained within the 1 to 20 mA range. The FAN5610 is
available in an 8-lead 3X3 MLP package.
• Cell Phones
• Handheld Computers
• PDA, DSC, MP3 Players
• LCD Display Modules
• Keyboard Backlight
• LED Displays
Typical Application
VIN
D4
D3
D2
D1
VIN
IN A
D
A
C
FAN5610
GND
IN B
REV. 1.0.2 10/28/03
FAN5610
PRODUCT SPECIFICATION
Pin Assignment
GND
D4
D1
D2
IN B
IN A
FAN5610
D3
VIN
3x3mm 8-LEAD MLP PACKAGE
Pin Descriptions
Pin Name
D1
Pin Function Description
Cathode of Diode No.1
Cathode of Diode No. 2
DAC Input B, Active High
DAC Input A, Active High
Input Voltage
D2
IN B
IN A
VIN
D3
Cathode of Diode No. 3
Cathode of Diode No. 4
Ground
D4
GND
2
REV. 1.0.2 10/28/03
PRODUCT SPECIFICATION
FAN5610
Absolute Maximum Ratings
Parameter
Min.
Max.
6.0
Unit
VIN, IN A/IN B Voltage to GND
Lead Soldering Temperature (10 seconds)
Operating Junction Temperature Range
Storage Temperature
-0.3
V
300
150
150
°C
°C
°C
kV
-55
4
Electrostatic Discharge Protection Level (Note1)
HBM
CDM
2
Recommended Operating Conditions
Parameter
Min.
2.7
Typ.
Max.
5.5
Unit
V
Input Voltage Range, VIN (Note2)
Operating Ambient Temperature Range
-40
25
85
°C
DC Electrical Characteristics
(VIN =3.3V to 5.5V, TA = 25 °C, unless otherwise noted. Boldface values indicate specifications over the ambient
operating temperature range.)
Parameter
Conditions
Min.
Typ.
Max.
2
Units
Supply Current, OFF Mode
IN A = 0
IN B = 0
<1
µA
Output Current Accuracy
VD > 0.3V
IN A = 1, IN B = 1
14.8
-7.5
21
26
mA
%
LED to LED Current Matching
DAC Input Voltage Threshold
VIN = 3.6V
IN A = 1, IN B = 1
7.5
LOW
HIGH
0
0.3 × VIN
V
0.6 × VIN
VIN
Peak Efficiency
LED VF =3V at 20mA
91
%
Notes:
1. Using Mil Std. 883E, method 3015.7(Human Body Model) and EIA/JESD22C101-A (Charge Device Model).
2. The minimum operating voltage depends on the LED’s operating voltage, as shown in the "Application Information" section.
REV. 1.0.2 10/28/03
3
FAN5610
PRODUCT SPECIFICATION
Block Diagram
V
D1
D2
IN
D3
+
+
Error Ampl.
-
Error Ampl.
-
10Ω
Bandgap
Reference
2-bit
DAC
10Ω
D4
+
+
Error Ampl.
-
Error Ampl.
-
IN A
IN B
10Ω
10Ω
GND
4
REV. 1.0.2 10/28/03
PRODUCT SPECIFICATION
FAN5610
Typical Performance Characteristics
Unless otherwise specified, TA = 25 °C, using Fairchild QTLP670IW Super Bright LED.
LED Current vs. Input Voltage
LED Current vs. Cathode Voltage
(Low V - White LED)
F
25
20
15
10
5
25
20
15
10
5
A = 1, B = 1
A = 0 , B = 1
A = 1, B = 1
A = 0, B = 1
A = 1, B = 0
A = 1, B = 0
0
2.5
0
0.0
3.0
3.5
4.0
4.5
5.0
5.5
0.5
1.0
1.5
2.0
2.5
Input Voltage (V)
Cathode Voltage (V)
LED Current vs. Temperature
Line Transient Response
25
20
15
10
5
VIN = 5V
A = 1, B = 1
A = 0 , B = 1
VIN = 4 V
A = 1 , B = 0
-40
-20
0
20
40
60
80
Time (2µs/div)
Temperature (°C)
DAC Transient Response
A = 1, B = 1
A = 0, B = 0
ILE D = 0m A
ILED = 21 m A
Time (50µs/div)
REV. 1.0.2 10/28/03
5
FAN5610
PRODUCT SPECIFICATION
2. Digital Control with PWM
Digital LED Brightness Control
Any pin can be modulated by a variable duty cycle (δ) pulse
train. Care should be taken not to use too low frequency,
otherwise a flickering effect can be seen.The minimum range
is between 100Hz to 5KHz. For a maximum range of LED
current, both A and B can be modulated at the same time.
1. Digital Control
A digital to analog converter selects the following modes of
operation: OFF, 7mA, 14mA, 21mA per diode. In addition,
by turning the "IN B" pin ON and OFF , the current can be
modulated between 8 to 20mA to achieve any Iaverage value.
A
B
0
0
1
0
0
1
1
1
ILED
OFF
7mA
14mA
21mA
Digital Control with PWM
A is PWM and B is Low. ILED (Average) = δ x 7mA where δ is Duty Cycle. (Note 3)
A Input (PWM)
30%
Duty Cycle
70%
Duty Cycle
1KHz
1KHz
B Input (0)
ILED (Average) = 0.7 x 7mA = 4.9mA
ILED (Average) = 0.3 x 7mA = 2.1mA
I
0mA
OFF
LED
A is High and B is PWM. ILED (Average) = 7mA + δ x 14mA where δ is Duty Cycle. (Note 4, 5)
A Input
B Input (PWM)
70%
Duty Cycle
30%
Duty Cycle
1KHz
1KHz
ILED (Average) = 7mA + 0.7 x 14mA = 16.8mA
ILED (Average) = 7mA + 0.3 x 14mA = 11.2mA
I
OFF
0mA
LED
Notes:
3. Proportionally select the duty cycle to achieve a typical LED current between 1mA to 6mA.
4. If either input A or B is high continuously, the other input can be modulated at a maximum rate of 30kHz. If this is not the
case, the maximum rate of modulation should be limited to 1kHz.
5. Proportionally select the duty cycle to achieve a typical LED current between 8mA to 20mA.
6
REV. 1.0.2 10/28/03
PRODUCT SPECIFICATION
FAN5610
Digital Control with PWM (Continued)
A and B are PWM. ILED (Average) = δ x 21mA where δ is Duty Cycle. (Note 6)
A Input (PWM)
70%
Duty Cycle
30%
Duty Cycle
1KHz
1KHz
B Input (PWM)
30%
Duty Cycle
70%
Duty Cycle
ILED (Average) = 0.7 x 21mA = 14.7mA
ILED (Average) = 0.3 x 21mA = 6.3mA
0mA
OFF
I
LED
Note:
6. Proportionally select the duty cycle to achieve the desired value of typical LED current between 1mA to 20mA.
Program the LED’s brightness by applying a continuous
voltage level or a PWM signal at the inputs of the built-in
Application Information
As seen in the block diagram, the FAN5610 includes four
digital to analog converter (DAC). When a PWM signal is
independent current regulators able to maintain a program-
utilized to drive the DAC inputs, the current through the
mable constant current through LEDs, regardless of their for-
ward voltage. This is true over a wide range of input
voltage starting from VF_max + 0.35V, where VF_max is the
highest forward voltage among the LEDs driven by
LEDs is switched between two levels with the PWM signal
frequency. Consequently, the average current changes with
the duty cycle. The LED current waveform tracks the PWM
signal, so the LEDs brightness depends on the duty cycle.
FAN5610. The independence of current (LED current
changes less than 1%) with change in VIN and VF for
VIN > VF (MAX) + 0.35V, is shown in the graph below.
For white LEDs the spectral composition is optimal at a
current level specified by the manufacturer. The DAC inputs
should be programmed to set the current required to achieve
white LED spectrum and PWM used for dimming. To main-
tain the "purest" white, the current through the LEDs should
Current Regulation Performance
25
be switched between zero and a specified current level
(usually around 20mA) corresponding to the white light
chromaticity coordinate.
VF1 = 3.3V
20
VIN > V F (MAX) + 0.3 5V
15
Conversion errors are minimized and the best LED to LED
matching is achieved over the entire range of average current
settings, when PWM brightness control is used to modulate
10
VF2 =3.6V
the LED current between zero and the maximum value
5
(A=1, B=1).
0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
Input Voltage (V)
REV. 1.0.2 10/28/03
7
FAN5610
PRODUCT SPECIFICATION
– VDROP ~ 0.35V
– VF (at 20mA) = 3.3V to 4.0V (High VF)
Application Examples:
Example 1: Drive low VF white or blue LEDs directly
from single cell Li-ion
– VIN(at 20mA) ≥ VDROP + VF = 4.35V(max)
Where VIN = Existing bus = 5V
When using white or blue low VF LEDs, and utilizing the
driver’s low voltage drop, only 3.45V in VIN is needed for
the full 20mA LED current. Usually at 3.1V, there is still
5mA current available for the LEDs. The single cell Li-ion is
utilized in most applications like cell phones or digital still
cameras. In most cases, the Li-ion battery voltage level only
goes down to 3.0V voltage level, and not down to the full
discharge level (2.7V) before requesting the charger.
(System Bus)
V
IN
D4
D3
D2
D1
VIN
FAN5610
IN A
Microprocessor
I/O
(Li-Ion)
V
IN
IN B
GND
D4
D3
D2
D1
VIN
Key advantages:
• No boost circuit needed for LCD or keyboard backlight
• Driver utilizes the existing bus
• Low voltage drop provides the full 20mA LED current at
the lowest possible voltage level.
FAN5610
IN A
IN B
Micro-Controller
GND
– VDROP ~ 0.35V
– VF (at 20mA) < 3.1V (Low VF)
– VIN (at 20mA) =VDROP + VF = 3.45V
– VIN (at 5mA Typical) ~ 3.1V
Where VIN = Single cell Li-ion Voltage
Key advantages:
• No boost circuit needed for the LCD or keyboard
backlight
• Driver directly connected to a Li-ion battery
• No EMI, no switching noise, no boost efficiency lost, no
capacitor, and no inductor.
Example 2: Drive high VF white or blue LEDs from
existing bus from 4.0V to 5.5V
High VF white or blue LEDs have forward-voltage drop in
the range of 3.3V to 4.0V. To drive these LEDs with the max-
imum current of 20mA for maximum brightness, usually
requires a boost circuit for a single cell Li-ion voltage range.
In some cases, there is already a voltage bus in the system,
which can be utilized. Due to the low voltage drop of the
FAN5610, VIN needs to be only 350mV higher than the
voltage VF of LEDs connected to FAN5610.
8
REV. 1.0.2 10/28/03
PRODUCT SPECIFICATION
FAN5610
Mechanical Dimensions
3mmX3mm 8-Lead MLP Package
2.37
3.0
A
B
0.15 C
2X
4
1
1.99
1.42
3.30
3.0
(0.65)
5
8
0.47 TYP
0.15 C
0.65 TYP
2X
TOP VIEW
1.0 MAX
0.10 C
RECOMMENDED LAND PATTERN
(0.20)
0.08 C
0.05
0.00
C
SEATING
PLANE
SIDE VIEW
2.25
MAX
1
4
0.45
0.20
1.30 MAX.
0.25~0.35
5
8
0.65
M
Ø0.10 C A B
1.95
M
Ø0.05
BOTTOM VIEW
NOTES:
A. CONFORMS TO JEDEC REGISTRATION MO-229,
VARIATION VEEC, DATED 11/2001
B. DIMENSIONS ARE IN MILLIMETERS.
C. DIMENSIONS AND TOLERANCES PER
ASME Y14.5M, 1994
REV. 1.0.2 10/28/03
9
FAN5610
PRODUCT SPECIFICATION
Ordering Information
Product Number
Package Type
Order Code
FAN5610
3x3mm 8-Lead MLP
FAN5610MPX
DISCLAIMER
FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO
ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD 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.
LIFE SUPPORT POLICY
FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES
OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR
CORPORATION. As used herein:
1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the body,
or (b) support or sustain life, and (c) whose failure to
perform when properly used in accordance with
instructions for use provided in the labeling, can be
reasonably expected to result in a significant injury of the
user.
2. A critical component in any component of a life support
device or system whose failure to perform can be
reasonably expected to cause the failure of the life support
device or system, or to affect its safety or effectiveness.
www.fairchildsemi.com
10/28/03 0.0m 005
Stock#DS30005609
2003 Fairchild Semiconductor Corporation
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