MIC2299
3.5A Minimum, 2MHz High Brightness
LED Driver
General Description
The MIC2299 is a high power boost-switching regulator
that is optimized for constant-current control. The MIC2299
is capable of driving up to 2 series 1A white LED for
photoflash and other applications. The feedback voltage is
only 200mV, minimizing power dissipation in constant-
current control applications, and hence extends battery
life.
The MIC2299 has a brightness pin that allows for a
programmable torch mode as well as full flash with a
single pin when driving high current LEDs.
The MIC2299 implements a constant frequency 2MHz
PWM control scheme to make the smallest possible
design. The MIC2299’s 2MHz operation avoids signal
interference in the AM band.
The 2.5V to 10V input voltage range of MIC2299 allows
direct operation from 1- and 2-cell Li-Ion as well as 3- to 4-
cell NiCad/ NiMH/ Alkaline or lithium batteries. Maximum
battery life is assured with a low 1uA shutdown current.
The MIC2299 is available in a low profile 12-pin 3mm x
3mm MLF
®
package.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Programmable current control
200mV
±10%
feedback voltage
2.5V to 10V input voltage
Output over-voltage protection (OVP)
Output voltage up to 30V (max)
Fixed 2MHz Operation
Guaranteed 3.5A switch current over-temperature
Solution size of just 0.25in
2
(1.6cm
2
)
Output power range of 7W to 12W
<1% line regulation
1µA shutdown current
Over temperature protection
Externally programmable soft-start
Under-voltage lockout (UVLO)
12-pin 3mm x 3mm leadless MLF
®
package
–40
°
C to +125
°
C junction temperature range
Applications
•
•
•
•
Cell phones
PDAs
Digital cameras
White LED flashlights
___________________________________________________________________________________________________________
Typical Application
Figure 1. High Power White LED Driver
MLF and
MicroLeadFrame
are registered trademarks of Amkor Technology, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
October 2007
M9999-101907-B
Micrel, Inc.
MIC2299
Ordering Information
Part Number
MIC2299-15YML
Note
MLF® is a GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
OVP
15V
Frequency
2MHz
Junction Temp. Range
–40° to +125°C
Package
12-Pin 3x3 MLF
®
Lead Finish
Pb-Free
Pin Configuration
BRT
SS/DIM
FB
AGND
PGND
PGND
1
2
3
4
5
6
EP
12 COMP
11 EN
10 VIN
9
8
7
OVP
SW
SW
12-Pin 3mm x 3mm MLF (ML)
(Top View)
Pin Description
Pin Number
1
Pin Name
BRT
Pin Function
BRT (Input): Short this pin to GND to achieve 20% I
OUT
(1V gives I
OUT
at 100%).
As an alternative connect a resistor to GND to control the I
OUT
to >0.2I
OUT
. . A
10µA current source sets the voltage on the resistor. Hence a 50K resistor
would yield 0.5V which would be 50% of I
OUT
nominal.
Soft start/dimming (input) 40k
Ω
source from V
FB
. Connect a capacitor to GND
for soft-start. Clamp the pin to a known voltage to control the internal reference
voltage and hence the output current. This can also be done with a resistor to
GND
Feedback (Input): Output voltage sense node. Connect the cathode of the LED
to this pin.
Analog Ground
Power Ground
Switch Node (Input): Internal power BIPOLAR collector.
Over-Voltage Protection (OVP): Connect to the output voltage to clamp the
maximum output voltage. A resistor divider from this pin to ground could be
used to raise the OVP level beyond 15V (max).
Supply (Input): 2.5V to 10V for internal circuitry.
Enable (Input): Logic High enables regulator. Logic Low shuts down regulator.
Compensation pin (Input): Add external R and C to GND to stabilize the
converter.
Ground (Return): Backside exposed pad.
2
SS/DIM
3
4
5,6
7,8
9
FB
AGND
PGND
SW
OVP
10
11
12
Pad
VIN
EN
COMP
EP
October 2007
2
M9999-101907-B
Micrel, Inc.
MIC2299
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) .......................................................12V
Switch Voltage (V
SW
)....................................... –0.3V to 34V
BRT Voltage (V
BRT
) ........................................... –0.3V to 6V
Enable Voltage (V
EN
)....................................... –0.3V to 12V
FB Voltage (V
FB
)...............................................................6V
Switch Current (I
SW
) ..................................Internally Limited
Ambient Storage Temperature (T
s
) ...........–65°C to +150°C
ESD Rating
(3)
.................................................................. 2kV
Operating Ratings
(2)
Supply Voltage (V
IN
).......................................... 2.5V to 10V
BRT Voltage (V
BRT
) ........................................... 0V to 0.6V
IN
Enable Voltage (V
EN
).............................................. 0V to V
IN
Output Voltage (V
OUT
) ................................... V
IN
+ 1 to V
OVP
Junction Temperature (T
J
) ........................ –40°C to +125°C
Package Thermal Impedance
3x3 MLF-12 (θ
JA
) ...............................................60°C/W
Electrical Characteristics
(4)
T
A
= 25°C; V
IN
= V
EN
= 3.6V; V
OUT
= 7V; I
OUT
= 1A, unless otherwise noted.
Bold
values indicate –40°C< T
J
< +125°C.
Symbol
V
IN
V
UVLO
V
OVP
I
VIN
I
SD
V
FB
I
FB
Parameter
Supply Voltage Range
Under-Voltage Lockout
Over-Voltage Protection
Quiescent Current
Shutdown Current
Feedback Voltage
Feedback Input Current
Line Regulation
LED Dimming Accuracy
(% of V V
FBNOM
),
Note 6
Condition
Min
2.5
1.8
12
Typ
2.1
13.5
15
0.1
Max
10
2.4
15
23
1
216
220
Units
V
V
V
mA
µA
mV
mV
nA
%
V
FB
>200mV, Not Switching
V
EN
= 0V (
Note 5
)
(±8%)
(±10%) (Over Temp)
V
FB
= 200mV
2.5V
≤
V
IN
≤
4.5V
V
BRT
= GND
R
BRT
= 50K
184
180
200
–450
0.5
17
45
90
20
50
23
55
%
%
%
D
MAX
I
SW
V
SW
I
SW
V
EN
I
EN
f
SW
I
SS
T
J
Notes:
Maximum Duty Cycle
Switch Current Limit
Switch Saturation Voltage
Switch Leakage Current
Enable Threshold
Enable Pin Current
Oscillator Frequency
Soft start / DIM current
Over-Temperature Threshold
Shutdown
V
IN
= 3V
V
IN
= 3.6V, I
SW
= 3.5A
V
EN
= 0V, V
SW
= 10V
TURN ON
TURN OFF
V
EN
= 10V
MIC2299
DIM = 0V
Hysteresis
3.5
4.75
350
0.01
8
500
A
mV
µA
V
V
µA
MHz
µA
10
0.4
1.5
20
40
1.75
2
5
150
10
2.3
°
C
°
C
1. Absolute maximum ratings indicate limits beyond which damage to the component may occur. Electrical specifications do not apply when operating
the device outside of its operating ratings. The maximum allowable power dissipation is a function of the maximum junction temperature, T
J(Max)
, the
junction-to-ambient thermal resistance,
θ
JA
, and the ambient temperature, T
A
. The maximum allowable power dissipation will result in excessive die
temperature, and the regulator will go into thermal shutdown.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended.
4. Specification for packaged product only.
5. I
SD
= I
VIN
6. As percentage of full brightness where V
IN
= V
BRT
= 3.6V (100% brightness)
October 2007
3
M9999-101907-B
Micrel, Inc.
MIC2299
Typical Characteristics
16
14
12
UVLO (V)
10
8
6
4
2
0
0
2
4
6
8
SUPPLY VOLTAGE (V)
10
1.9
1.8
TEMPERATURE (°C)
1.8
1.7
2
T
CASE
- 25°C
3
4 5 6 7 8 9 10 11
SUPPLY VOLTAGE (V)
Input Current
vs. Supply Voltage
2.4
2.3
2.2
2.1
2.0
UVLO
vs. Temperature
2.3
2.2
2.1
2.0
1.9
Switching Frequency
vs. Supply Voltage
2.3
2.2
2.1
2.0
1.9
1.8
1.7
Switching Frequency
vs. Temperature
240
230
220
210
200
190
180
170
LED Current vs.
Supply Voltage (BRT-GND)
1020
1010
1000
LED Current vs.
Supply Voltage (BRT Open)
990
980
970
960
160
2.5
TEMPERATURE (°C)
T
CASE
- 30°C
3
3.5
4
4.5
5
SUPPLY VOLTAGE (V)
5.5
950
2.5
T
CASE
- 30°C
3
3.5
4
4.5
5
5.5
SUPPLY VOLTAGE (V)
525
520
515
510
505
500
495
490
485
480
LED Current vs.
Supply Voltage (RBRT-50k)
1020
1010
1000
990
980
970
960
LED Current vs.
Temperature (BRT Open)
475
2.5
T
CASE
- 30°C
3 3.5 4 4.5 5 5.5 6
SUPPLY VOLTAGE (V)
950
-40 -20
V
IN
= 3V
0 20 40 60 80 100
TEMPERATURE (C)
1100
1000
900
800
700
600
500
400
300
200
100
0
0
LED Current
vs. DIM Voltage
40
80 120 160 200
DIM VOLTAGE (mV)
95
90
85
80
75
70
65
60
55
Efficiency vs.
Supply Voltage (BRT Open)
90
85
80
75
70
65
60
55
Efficiency vs.
Supply Voltage (BRT-GND)
450
400
350
300
250
200
150
100
50
VC
SAT
vs. Switching Current
50
2.5 3 3.5 4 4.5 5 5.5 6 6.5
SUPPLY VOLTAGE (V)
50
2.5 3 3.5 4 4.5 5 5.5 6 6.5
SUPPLY VOLTAGE (V)
0
0 0.5 1 1.5 2 2.5 3 3.5 4
SWITCHING CURRENT (A)
October 2007
4
M9999-101907-B
Micrel, Inc.
MIC2299
Typical Characteristics (continued)
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1 T
CASE
- 50°C
0
0
2
4
6
8 10 12
OUTPUT VOLTAGE (V)
V
IN
= 3V
Max DC LED Current
vs. Output Voltage
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
Max DC LED Current
vs. Output Voltage
V
IN
= 3.6V
V
IN
= 3V
V
IN
= 3.6V
14
0.2
0.1 T
CASE
- 25°C
0
0
2
4
6
8 10 12
OUTPUT VOLTAGE (V)
14
October 2007
5
M9999-101907-B
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