FAN5609 [FAIRCHILD]
LED Driver with Adaptive Charge Pump DC/DC Converter; LED驱动器，自适应电荷泵DC / DC转换器
| 型号： | FAN5609 |
| 厂家： | 
FAIRCHILD SEMICONDUCTOR |
| 描述： | LED Driver with Adaptive Charge Pump DC/DC Converter |
| 文件： | 总11页 (文件大小：114K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
www.fairchildsemi.com
FAN5609
LED Driver with Adaptive Charge Pump DC/DC
Converter
Features
Applications
• Parallel LED Driver Supports All Forward Voltages
• Adaptive VOUT Adjustment to the Highest Diode Voltage
• Internally Matched LED Current Sources
• No External Components Needed to Set LED Current
• Built-in Charge Pump has Three Modes of Operation:
– Linear Regulation VIN > 4.2V
• Cell Phones
• Handheld Computers
• PDA, DSC, MP3 Players
• Keyboard Backlight
• LED Displays
– 3/2 DC-DC Converter and Regulation 3.6V<VIN<4.2V
– 2/1 DC-DC Converter and Regulation 2.7V<VIN<3.6V
• Up to 86% Efficiency
Description
The FAN5609 generates regulated output current from a
battery with input voltage varying between 2.7V to 5.5V.
Switch reconfiguration and fractional switching techniques
are utilized to achieve high efficiency over the entire input
voltage range. A proprietary internal circuitry continuously
monitors each LED current loop and automatically adjusts
the generated output DC voltage to the lowest minimum
value required by the LED having the highest forward
voltage. This adaptive nature of the FAN5609 eliminates the
need for LED pre-selection (matching) and ensures opera-
tion at high efficiency. When the input voltage is sufficiently
high to sustain the programmed current level in the LEDs,
the FAN5609 re-configures itself to operate as a linear
regulator, and the DC-DC converter is turned off. An internal
two-bit digital to analog converter provides programmability
of the output currents. Only two 0.1µF bucket capacitors and
two 4.7µF input/output capacitors are needed for proper
operation.
• Low EMI, Low Ripple
• Up to 80mA Output Current (4 × 20mA)
• Built-in DAC for Digital or PWM Brightness Control
• Can be Duty Cycle Modulated between 0 to 18mA
• 2.7V to 5.5V Input Voltage Range
• ICC < 2µA in Shutdown Mode
• 1MHz Operating Frequency
• Shutdown Isolates Output from Input
• Soft-Start Limits Inrush Current
• Short Circuit Protection
• Minimal External Components Needed
• Available in a 14-lead TSSOP Package
• Available in a 16-lead MLP Package
Soft-start circuitry prevents excessive current draw during
power on. The device has built-in short circuit protection.
Typical Application
VOUT
COUT
VOUT LED-
VIN
LED-
LED-
LED-
CAP-
VIN
CIN
CAP2
CAP1
FAN5609
GND
CAP+
CAP+
IN A
IN B
D
A
C
CAP-
REV. 1.0.2 5/30/03
FAN5609
PRODUCT SPECIFICATION
Pin Assignments
Top-View
VIN
VOUT
CAP2-
CAP2+
16 15 14 13
VIN
1
12 CAP1+
GND
B
CAP1+
CAP1-
VOUT
11
2
3
CAP1-
10
GND
B
NC
NC
A
LED-
9
4
LED-
LED-
LED-
LED-
5
6
7
8
FAN5609
FAN5609
4x4mm 16-Lead MLP
14-Lead TSSOP
Pin Descriptions
FAN5609
Pin No.
14L-TSSOP
VIN
4mmX4mm 16L-MLP
Pin Function Description
1
2
VIN
VOUT
GND
B
Input
VOUT
GND
Output to LEDs Anode
Ground
3
4
B
DAC B
5
A
A
DAC A
6
LED -
LED -
LED -
LED -
NC
LED -
LED -
LED -
LED -
NC
4th LED Cathode
3rd LED Cathode
2nd LED Cathode
1st LED Cathode
No Connection
7
8
9
10
11
12
13
14
15
16
CAP1-
CAP1+
CAP2+
CAP2-
CAP1-
CAP1+
CAP2+
CAP2-
NC
Bucket capacitor negative terminal
Bucket capacitor positive connection
Bucket capacitor positive terminal
Bucket capacitor negative connection
No Connection
NC
No Connection
Test Circuit
CAP2
0.1µF
NC NC
V
IN
= 2.7V to 5.5V
16
13
12
1
CAP1
4.7µF
C
IN
0.1µF
V
OUT
FAN5609
NC
C
OUT
4.7µF
V
L
9
4
5
8
V
H
4 White LEDs
Fairchild QTLP670C-IW
Super Bright LED
V
H
V
L
All capacitors are Ceramic chip capacitor
2
REV. 1.0.2 5/30/03
PRODUCT SPECIFICATION
FAN5609
Absolute Maximum Ratings
Parameter
Min
-0.3
-0.3
Max
6.0
Unit
V
VIN, VOUT, A, B Voltage to GND
CAP+, CAP-, to GND
VIN + 0.3
INDEFINITE
300
V
VOUT Short Circuit Duration
Lead Soldering Temperature (10 seconds)
Operating Junction Temperature Range
Storage Temperature
°C
°C
°C
kV
150
-55
4
150
Electrostatic Discharge Protection Level (Note 1)
HBM
CDM
2
Recommended Operating Conditions
Parameter
Min
Typ
Max
5.5
85
Unit
Input Voltage Range, VIN
Operating Ambient Temperature Range
2.7
-40
V
25
°C
DC Electrical Characteristics
Unless otherwise noted, VIN =3V to 5.5V, TA = 25°C. Refer to “Test Circuit”. Boldface values indicate specifications
over the ambient operating temperature range.
Parameter
Conditions
Min.
Typ.
Max.
Units
Quiescent Current
VOUT = 5.5V,
No Load
1.5
4
mA
Output Current Accuracy
INOM = 20mA
A = High
B = High
17
20
23
mA
%
LED to LED Current Matching
VIN = 5.5V
-5
+5
A = B = High
Efficiency
VIN = 4.5V
VIN = 3V
85 to75
65 to 55
%
Input A, B Threshold
Low
0
0.3 × VIN
V
V
High
0.6 × VIN
VIN
VIN at Configuration
Change
From 1:1 to 3:2
From 3:2 to 2:1
4.2
3.6
1
Oscillator Frequency
0.80
1.2
2
MHz
Supply Current, "OFF Mode"
µA
Note:
1. Using Mil Std. 883E, method 3015.7(Human Body Model) and EIA/JESD22C101-A (Charge Device Model)
REV. 1.0.2 5/30/03
3
FAN5609
PRODUCT SPECIFICATION
Block Diagram
1µF
V
OUT
Linear
V
IN
Voltage
Regulator
Selector
A
B
DAC
D
R
I
Power
Good
P
U
M
P
V
E
R
S
Oscillator
On Off
And
Current Range
Bandgap
Reference
Reference
5µF
Analog
Detector
Range Selection
Low Battery Ref.
Ref2
Ref1
Regulator
Ref3
Mode Change
V
IN
Ref4 (BG)
GND
1µF
the voltage decays, the FAN5609 switches between modes to
maintain a constant current through LED throughout the bat-
tery life. The transition has hysteresis to prevent toggling.
Circuit Description
The FAN5609’s switched capacitor DC/DC converter auto-
matically configures its internal switches to achieve high effi-
ciency and to provide tightly regulated output currents for
the LEDs. An analog detector determines which diode
requires the highest voltage in order to sustain the pre-set
current levels, and adjusts the pump regulator accordingly.
Every diode has its own linear current regulator. In addition,
a voltage regulator controls the output voltage when the bat-
tery voltage is within a range where linear regulation can
provide maximum possible efficiency. If the battery voltage
is too low to sustain the diode current in the linear mode,
a fractional 3:2 charge pump is enabled. When the battery
voltage drops further and this mode is no longer sufficient to
sustain proper operation, the pump is automatically reconfig-
ured to operate in 2:1 mode. As the battery discharges and
Supply Voltage
The internal supply voltage for the device is automatically
selected from VIN or VOUT pins, whichever is higher.
Soft Start
The soft-start circuit limits inrush current when the device is
initially powered up and enabled. The reference voltage con-
trols the rate of the output voltage ramp-up to its final value.
Typical start-up time is 1ms. The rate of the output voltage
ramp-up is controlled by an internally generated slow ramp,
and an internal variable resistor limits the input current.
4
REV. 1.0.2 5/30/03
PRODUCT SPECIFICATION
FAN5609
Switch Configuration
V
IN
V
IN
V
OUT
+
CAP1
-
V
OUT
=
2 X V
IN
+
CAP2
C
OUT
-
GND
Figure 1
Step-up, 2:1 configuration.
Switch positions shown in charge phase.
Reverse all switches for pump phase.
GND
Figure 2
Step-up
3:2 configuration
Switch positions shown in charge phase.
Reverse all switches for pump phase.
Shutdown and Short Circuit Current Limit
Digital Control with PWM
Set both DAC inputs low to shut down the device. Built-in
short circuit protection limits the supply current to a maxi-
mum of 50mA.
Any input can be modulated by a pulse train of variable duty
cycle (δ). By turning ON and OFF DAC inputs A or B, the
current can be continuously modulated to any average value
between 1 to 19mA. For a maximum range of LED current,
both A&B can be modulated at the same time.
Digital Control
A digital-to-analog converter (DAC) allows selection of the
following modes: OFF, 7mA, 14mA, 20mA, per diode.
By turning the IN B pin ON and OFF, the current can be
modulated between 7 to 20mA to achieve any IAverage value
(PWM). In PWM mode, the modulating frequency has to be
set sufficiently high in order to avoid a flickering effect
(100Hz to 1kHz).
A
B
0
0
1
0
0
1
1
1
ILED
OFF
7mA
14mA
20mA
REV. 1.0.2 5/30/03
5
FAN5609
PRODUCT SPECIFICATION
Digital Control with PWM
A is PWM and B is Low. ILED (Average) = δ x 7mA, where δ is Duty Cycle. (Note 2)
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) = 6mA + δ x 12mA, where δ is Duty Cycle. (Note 3, 4)
A Input
B Input (PWM)
30%
Duty Cycle
70%
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:
2. Proportionally select the duty cycle to achieve a typical LED current between 1mA to 6mA.
3. If either input A or B is continuously high, the other input can be modulated at a maximum rate of 30kHz. Otherwise the
maximum rate of modulation should be limited to 1kHz.
4. Proportionally select the duty cycle to achieve a typical LED current between 8mA to 19mA.
6
REV. 1.0.2 5/30/03
PRODUCT SPECIFICATION
FAN5609
Digital Control with PWM (Continued)
A and B are PWM. ILED (Average) = δ x 20mA, where δ is Duty Cycle. (Note 3, 5)
A Input (PWM)
30%
Duty Cycle
70%
Duty Cycle
1KHz
1KHz
B Input (PWM)
70%
Duty Cycle
30%
Duty Cycle
ILED (Average) = 0.7 x 20mA = 14mA
ILED (Average) = 0.3 x 20mA = 6mA
0mA
OFF
I
LED
Notes:
5. Proportionally select the duty cycle to achieve a typical LED current between 1mA to 19mA.
CAP1 and CAP2 control the current capability of the charge
Application Information
pump and affect the overall efficiency of the system. A lower
value will improve efficiency, but it may limit the LED’s
currents at low input voltage. A capacitor of 100nF is opti-
mal for 4 × 20 mA load over the entire input voltage range of
2.7V to 4.2V. To save space and cost, and to increase effi-
ciency, this value may be reduced to 10nF for loads less than
4 x 7mA.
Selecting Capacitors
It is important to select the appropriate capacitor types and
the values for use with the FAN5609. These capacitors
determine parameters such as power efficiency, maximum
sustainable load current by the charge pump, input and
output ripple and start-up time.
Pulse-Width-Modulated (PWM) Mode
In order to reduce ripple, both CIN and COUT should be low
ESR capacitor. Increasing the COUT capacitor reduces the out-
put ripple voltage. However this will increase the power-on
time. The CIN value controls input ripple. If necessary, this
ripple can be further reduced by powering the FAN5609
through a very small series inductor filter, as shown in Figure 3.
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
the LED current between zero and the maximum value
(A=1, B=1).
PC Board Layout
For best performance, a solid ground plane is recommended
on the back side of the PCB. The ground tails of CIN and
COUT should be connected together close to the GND pin of
IC.
100nH
Input
Power
Supply
VIN
FAN5609
GND
4.7µF
0.1µF
Figure 3.
REV. 1.0.2 5/30/03
7
FAN5609
PRODUCT SPECIFICATION
Typical Performance Characteristics
TA = 25°C, CIN =COUT = 4.7µF, CAP1 = CAP2 = 0.1µF, using Fairchild’s QTLP670C-IW Super Bright LED.
Regulated LED Current vs
LED Forward Voltage
DAC Threshold Voltage vs
Input Voltage
2.2
2.0
1.8
1.6
20.4
20.2
20.0
19.8
19.6
1.4
1.2
1.0
3.0
3.2
3.4
3.6
3.8
2.5
3.0
3.5
4.0
4.5
5.0
5.5
LED Forward Voltage (V)
LED Forward Voltage (V)
Supply Current vs Input Voltage
(4 LEDs)
Regulated LED Current vs Input Voltage
180
160
140
120
100
80
25
A = 1, B = 1
20
15
10
A = 1, B = 1
A = 0, B = 1
A = 0, B = 1
A = 1, B = 0
60
40
20
0
5
0
A = 1, B = 0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
2.5
3.0
3.5
4.0
4.5
5.0
5.5
Input Voltage (V)
Input Voltage (V)
Efficiency vs Input Voltage
(4 LEDs x 20mA)
Shutdown Current vs Input Voltage
1.6
1.4
0.9
A = 0, B = 0
0.8
0.7
0.6
0.5
0.4
1.2
1.0
0.8
0.6
2.5
3.0
3.5
4.0
4.5
5.0
5.5
2.5
3.0
3.5
4.0
4.5
5.0
5.5
Input Voltage (V)
VIN(V)
8
REV. 1.0.2 5/30/03
PRODUCT SPECIFICATION
FAN5609
Mechanical Dimensions
14-Lead TSSOP Package
14
8
4.16 TYP 7.72 TYP
4.4 0.1
-B-
6.4
3.2
1.78 TYP
0.65
TYP
0.2
C
B
A
0.42
TYP
1
7
ALL LEAD TIPS
PIN #1 IDENT.
LAND PATTERN RECOMMENDATION
0.1 C
ALL LEAD TIPS
1.1 MAX
TYP
0.9
0.25
0 -8
0.10 0.05TYP
-C-
0.09-0.20
0.65 TYP
0.6 0.1
0.19 - 0.30 TYP
SEATING PLANE
M
C
S
0.19-0.30
BS
REV. 1.0.2 5/30/03
9
FAN5609
PRODUCT SPECIFICATION
Mechanical Dimensions
4mmX4mm 16-Lead MLP Package
2.64
16
13
4.0
A
0.15 C
B
2X
1
12
3.04
4.50
2.64
4.0
4
9
(0.73)
5
8
0.15 C
0.65 TYP
0.42 TYP
2X
TOP VIEW
1.00 MAX
RECOMMENDED LAND PATTERN
0.10 C
(0.20)
C
0.05
0.00
SEATING
PLANE
SIDE VIEW
2.80
2.50
8
5
4
1
9
2.80
2.50
0.65
12
PIN #1 IDENT
16
0.65
13
0.25~0.35
M
0.10
0.10
C A B
M
C
BOTTOM VIEW
NOTES:
A. CONFORMS TO JEDEC REGISTRATION MO-220,
VARIATION VGGC-3, DATED AUG/2002
B. DIMENSIONS ARE IN MILLIMETERS.
C. DIMENSIONS AND TOLERANCES PER
ASME Y14.5M, 1994
10
REV. 1.0.2 5/30/03
FAN5609
PRODUCT SPECIFICATION
Ordering Information
Product Number
Package Type
14-Lead TSSOP
Order Code
FAN5609
FAN5609MTCX
FAN5609MPX
4mmx4mm 16-Lead MLP
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
5/30/03 0.0m 005
Stock#DS30005609
2003 Fairchild Semiconductor Corporation
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