Micrel MIC2299 3.5a minimum, 2mhz high brightness led driver Datasheet

MIC2299
3.5A Minimum, 2MHz High Brightness
LED Driver
General Description
Features
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 constantcurrent 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 4cell 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.
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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 0.25in2 (1.6cm2)
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
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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
OVP
Frequency
Junction Temp. Range
Package
Lead Finish
MIC2299-15YML
15V
2MHz
–40° to +125°C
12-Pin 3x3 MLF®
Pb-Free
Note
MLF® is a GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
Pin Configuration
BRT
1
12 COMP
SS/DIM
2
11 EN
FB
3
10 VIN
AGND
4
9
OVP
PGND
5
8
SW
PGND
6
7
SW
EP
12-Pin 3mm x 3mm MLF (ML)
(Top View)
Pin Description
Pin Number
Pin Name
Pin Function
1
BRT
2
SS/DIM
3
FB
4
AGND
Analog Ground
5,6
PGND
Power Ground
BRT (Input): Short this pin to GND to achieve 20% IOUT (1V gives IOUT at 100%).
As an alternative connect a resistor to GND to control the IOUT to >0.2IOUT. . A
10µA current source sets the voltage on the resistor. Hence a 50K resistor
would yield 0.5V which would be 50% of IOUT nominal.
Soft start/dimming (input) 40kΩ source from VFB. 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.
7,8
SW
Switch Node (Input): Internal power BIPOLAR collector.
9
OVP
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).
10
VIN
Supply (Input): 2.5V to 10V for internal circuitry.
11
EN
Enable (Input): Logic High enables regulator. Logic Low shuts down regulator.
12
COMP
Pad
EP
October 2007
Compensation pin (Input): Add external R and C to GND to stabilize the
converter.
Ground (Return): Backside exposed pad.
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Micrel, Inc.
MIC2299
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VIN) .......................................................12V
Switch Voltage (VSW)....................................... –0.3V to 34V
BRT Voltage (VBRT) ........................................... –0.3V to 6V
Enable Voltage (VEN)....................................... –0.3V to 12V
FB Voltage (VFB)...............................................................6V
Switch Current (ISW) ..................................Internally Limited
Ambient Storage Temperature (Ts) ...........–65°C to +150°C
ESD Rating(3) .................................................................. 2kV
Supply Voltage (VIN).......................................... 2.5V to 10V
BRT Voltage (VBRT) ........................................... 0V to 0.6VIN
Enable Voltage (VEN).............................................. 0V to VIN
Output Voltage (VOUT) ................................... VIN + 1 to VOVP
Junction Temperature (TJ) ........................ –40°C to +125°C
Package Thermal Impedance
3x3 MLF-12 (θJA) ...............................................60°C/W
Electrical Characteristics(4)
TA = 25°C; VIN = VEN = 3.6V; VOUT = 7V; IOUT = 1A, unless otherwise noted. Bold values indicate –40°C< TJ < +125°C.
Symbol
Parameter
VIN
Supply Voltage Range
Condition
2.5
VUVLO
Under-Voltage Lockout
1.8
2.1
2.4
V
VOVP
Over-Voltage Protection
12
13.5
15
V
IVIN
Quiescent Current
VFB >200mV, Not Switching
15
23
mA
ISD
Shutdown Current
VEN = 0V (Note 5)
0.1
1
µA
VFB
Feedback Voltage
(±8%)
(±10%) (Over Temp)
200
216
220
mV
mV
IFB
Feedback Input Current
VFB = 200mV
Line Regulation
2.5V ≤ VIN ≤ 4.5V
LED Dimming Accuracy
(% of V VFBNOM), Note 6
VBRT = GND
RBRT = 50K
DMAX
Maximum Duty Cycle
ISW
Switch Current Limit
VSW
Switch Saturation Voltage
ISW
Switch Leakage Current
VEN
Enable Threshold
TURN ON
TURN OFF
IEN
Enable Pin Current
VEN = 10V
Min
184
180
17
45
Typ
Max
Units
10
V
–450
nA
0.5
%
20
50
23
55
%
90
VIN = 3V
%
%
4.75
8
A
VIN = 3.6V, ISW = 3.5A
350
500
mV
VEN = 0V, VSW = 10V
0.01
10
µA
0.4
V
V
20
40
µA
2
2.3
MHz
fSW
Oscillator Frequency
MIC2299
ISS
Soft start / DIM current
DIM = 0V
TJ
Over-Temperature Threshold
Shutdown
Hysteresis
3.5
1.5
1.75
5
µA
150
°C
10
°C
Notes:
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, TJ(Max), the
junction-to-ambient thermal resistance, θ JA, and the ambient temperature, TA. 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. ISD = IVIN
6. As percentage of full brightness where VIN = VBRT = 3.6V (100% brightness)
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MIC2299
Typical Characteristics
16
Input Current
vs. Supply Voltage
UVLO
vs. Temperature
2.4
14
2.3
2.3
2.2
2.2
2.1
2.1
2.0
2.0
1.9
1.9
1.8
1.8
1.7
2
Switching Frequency
vs. Supply Voltage
12
UVLO (V)
10
8
6
4
2
0
0
2.3
2
4
6
8
SUPPLY VOLTAGE (V)
10
Switching Frequency
vs. Temperature
2.2
TEMPERATURE (°C)
LED Current vs.
Supply Voltage (BRT-GND)
2.1
1020
230
1010
1000
210
990
200
2.0
980
190
1.9
970
180
1.8
960
170
1.7
160
2.5
TCASE - 30°C
TEMPERATURE (°C)
3
3.5
4
4.5
5
SUPPLY VOLTAGE (V)
LED Current vs.
Supply Voltage (RBRT-50k)
LED Current vs.
Temperature (BRT Open)
525
520
1000
510
505
990
500
495
980
490
475
2.5
5.5
1010
515
485
480
1020
970
960
TCASE - 30°C
3 3.5 4 4.5 5 5.5 6
SUPPLY VOLTAGE (V)
Efficiency vs.
Supply Voltage (BRT Open)
950
-40 -20
VIN = 3V
0 20 40 60 80 100
TEMPERATURE (C)
Efficiency vs.
Supply Voltage (BRT-GND)
950
2.5
1100
1000
900
800
700
600
500
400
300
200
100
0
0
95
90
450
90
85
400
85
80
350
80
75
70
65
TCASE - 30°C
3
3.5
4
4.5
5
5.5
SUPPLY VOLTAGE (V)
LED Current
vs. DIM Voltage
40
80 120 160 200
DIM VOLTAGE (mV)
VCSAT
vs. Switching Current
300
75
250
70
200
65
150
60
60
100
55
55
50
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)
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4 5 6 7 8 9 10 11
SUPPLY VOLTAGE (V)
LED Current vs.
Supply Voltage (BRT Open)
240
220
TCASE - 25°C
3
4
0
0 0.5 1 1.5 2 2.5 3 3.5 4
SWITCHING CURRENT (A)
M9999-101907-B
Micrel, Inc.
MIC2299
Typical Characteristics (continued)
1.0
0.9
Max DC LED Current
vs. Output Voltage
0.8
0.7
0.6
1.0
0.9
VIN = 3.6V
VIN = 3V
0.8
0.7
0.6
Max DC LED Current
vs. Output Voltage
VIN = 3.6V
VIN = 3V
0.5
0.4
0.5
0.4
0.3
0.3
0.2
0.1 T
CASE - 50°C
0
0
2
4
6
8 10 12
OUTPUT VOLTAGE (V)
0.2
0.1 T
CASE - 25°C
0
0
2
4
6
8 10 12
OUTPUT VOLTAGE (V)
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MIC2299
Functional Characteristics
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MIC2299
Functional Diagram
Figure 2. MIC2299 Block Diagram
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MIC2299
diode (D1). Waveform 5 in Functional characteristics
shows Input Voltage ripple, Output Voltage ripple, SW
Voltage, and Inductor Current for 900mA LED current.
Regulation is achieved by modulating the pulse width i.e.
pulse-width modulation (PWM).
Functional Description
The MIC2299 is a constant frequency, pulse-widthmodulated (PWM) peak current-mode step-up regulator.
The MIC2299 simplified control scheme is illustrated in
the block diagram in Figure 2. A reference voltage is fed
into the PWM engine where the duty cycle output of the
constant frequency PWM engine is computed from the
error, or difference, between the REF and FB voltages.
The PWM engine encompasses the necessary circuit
blocks to implement a current-mode boost switch-mode
power supply. The necessary circuit blocks include, but
are not limited to, an oscillator/ramp generator, slope
compensation ramp generator, gm error amplifier, current
amplifier, PWM comparator, and drive logic for the
internal bipolar power transistor.
Inside the PWM engine the oscillator functions as a
trigger for the PWM comparator that turns on the bipolar
power transistor and resets the slope compensation
ramp generator. The current amplifier is used to
measure the power transistor’s current by amplifying the
voltage signal from the CS+ and CS- inputs from the
sense resistor connected to the emitter of the bipolar
power transistor. The output of the current amplifier is
summed with the output of the slope compensation ramp
generator where the result is connected to one of the
inputs of the PWM comparator.
The gm error amplifier measures the white LED current
through the external sense resistor and amplifies the
error between the detected voltage signal from the
feedback, or FB pin and the internal reference voltage.
The output of the gm error amplifier provides the voltage
loop signal that is fed to the other input of the PWM
comparator. When the current loop signal exceeds the
voltage loop signal the PWM comparator turns off the
power transistor. The next oscillator/clock period initiates
the next switching cycle, maintaining the constant
frequency current-mode PWM control. The white LED
current is set by the feedback resistor (the resistor
connected from the feedback pin to ground):
I LED =
Figure 3. Typical Application Circuit
Duty Cycle Considerations
Duty cycle refers to the switch on-to-off time ratio and
can be calculated as follows for a boost regulator:
D = 1−
However, at light loads the inductor will completely
discharge before the end of a switching cycle. The
current in the inductor reaches 0A before the end of the
switching cycle. This is known as discontinuous
conduction mode (DCM). DCM occurs when:
I out <
Vin I peak
⋅
2
Vout
Where
I peak =
(Vout
− Vin ) ⎛ Vin
⋅ ⎜⎜
L⋅f
⎝ Vout
⎞
⎟
⎟
⎠
In DCM, the duty cycle is smaller than in continuous
conduction mode. In DCM the duty cycle is given by:
200mV
R FB
D=
The enable pin shuts down the output switching and
disables control circuitry to reduce input current to
leakage levels. Enable pin input current is zero at zero
volts.
f ⋅ 2 ⋅ L ⋅ I out ⋅ (Vout − Vin )
Vin
The duty cycle required for voltage conversion should be
less than the maximum duty cycle of 90%. Also, in light
load conditions where the input voltage is close to the
output voltage, the minimum duty cycle can cause pulse
skipping. This is due to the energy stored in the inductor
causing the output to overshoot slightly over the
regulated output voltage. During the next cycle, the error
amplifier detects the output as being high and skips the
following pulse. This effect can be reduced by increasing
the minimum load or by increasing the inductor value.
Increasing the inductor value also reduces the peak
current.
DC-to-DC PWM Boost Conversion
The MIC2299 is a constant-frequency boost converter. It
operates by taking a DC input voltage and regulating a
higher DC output voltage. Figure 3 shows a typical
circuit. Boost regulation is achieved by turning on an
internal switch, which draws current through the inductor
(L1). When the switch turns off, the inductor’s magnetic
field collapses. This causes the current to be discharged
into the output capacitor through an external Schottky
October 2007
Vin
Vout
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MIC2299
Hence, a 200mΩ sense resistor will achieve nominally
1A when both DIM and BRT pins are left open.
Over-Voltage Protection
The MIC2299 offers over-voltage protection functionality.
If an LED is disconnected from the circuit or the
feedback pin is shorted to ground, the feedback pin will
fall to ground potential. This will cause the MIC2299 to
switch at full duty cycle in an attempt to maintain the
feedback voltage. As a result, the output voltage will
climb out of control. This may cause the switch node
voltage to exceed its maximum voltage rating, possibly
damaging the IC and the external components. To
ensure the highest level of protection, the MIC2299 OVP
pin will shut the switch off when an over-voltage
condition is detected, saving itself and the output
capacitor from damage. OVP threshold can be increase
by adding a resistor divider between the output and
ground. Be careful not to exceed the 30V rating of the
switch.
PWM control of brightness
A control signal can be driven into the enable pin to vary
average current through the LED for applications not
sensitive to low frequency (~100Hz) light modulation.
For such applications, the SS/DIM pin capacitance
should be minimized to achieve a fast turn on time. An
absent capacitor at the SS pin will achieve a soft start
period of approximately 1ms with a CCOMP value of 33nF.
For other applications, where no analog control voltage
is available, the BRT pin can be driven through a low
pass filter (18kΩ and 470nF) at a PWM frequency of
>5kHz to set the FB voltage, and therefore, the LED
current from 20% to 100% of Nominal LED current
(Figure 5).
Figure 5. High Frequency PWM Programming
Via BRT Pin
Figure 4. Adjustable OVP circuit
Since the DIM pin is typically utilized for soft start, it is
recommended to use the enable and BRT pins for the
PWM method of adjusting the average LED current.
Figures 6 and 7 below show typical results for this
method.
Brightness Control
Pin Brightness Functionality
BRT Pin
VFB (V)
OPEN
200mV or VSS/DIM
GND
40mV
≥20kΩ to 100kΩ
[RBRT] to GND
(10µA × RBRT)/5
SS/DIM
VFB (V)
OPEN
200mV
VSS/DIM
VSS/DIM
Table 1. BRT and SS/DIM Brightness Control Functionality
The MIC2299 has built in brightness/dimming
functionally for white LED applications. The BRT and
SS/DIM pins are available for brightness/dimming control
functionality. The table in Table 1 illustrates the different
modes of dimming offered by the BRT and SS/DIM pins.
The resulting LED current is then calculated as:
ILED = VFB/RSENSE
October 2007
Figure 6. Enable Pin PWM Freq = 100Hz
Enable Pin Programming
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MIC2299
Soft Start Functionality
The soft start time is dependent on both CSS and the
comp capacitor values. CCOMP is fixed for stable
operation (typically 33nF); therefore, if any increases in
soft start are desired, this should be done using the CSS
capacitor. The approximate total startup time (in
milliseconds) is given by the larger of: TSS = 1ms + 200k ⋅ C SS
Or
TSS = 1ms + CCOMP / 44 ⋅ 10 −6
E.g. for CCOMP = 33nF, use values of CCOMP > 4.3nF to
increase startup time from 1.75ms. The soft start
capacitor should be connected from the SS/DIM pin to
ground.
Figure 7. BRT Pin PWM Freq = 5kHz
BRT PWM Programming
Should the SS/DIM pin be used for voltage programming
the LED current, note that there will be a small offset due
to mismatches between the FB input and the impedance
driving the SS/DIM pin.
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MIC2299
Diode Selection
The MIC2299 requires an external diode for operation. A
Schottky diode is recommended for most applications
due to their lower forward voltage drop and reverse
recovery time. Ensure the diode selected can deliver the
peak inductor current and the maximum reverse voltage
is rated greater than the output voltage. Some lower
voltage Schottky diodes have a high reverse leakage
current when hot. This can cause high operating
currents during OVP. Using a 40V rated Schottky will
minimize such undesirable behavior.
Component Selection
Inductor
Inductor selection is a balance between efficiency,
stability, cost, size, and rated current. For most
applications a 2.2µH is the recommended inductor
value. It is usually a good balance between these
considerations. Larger inductance values reduce the
peak-to-peak ripple current, affecting efficiency. This has
the effect of reducing both the DC losses and the
transition losses. There is also a secondary effect of an
inductor’s DC resistance (DCR). The DCR of an inductor
will be higher for more inductance in the same package
size. This is due to the longer windings required for an
increase in inductance. Since the majority of input
current (minus the MIC2299 operating current) is passed
through the inductor, higher DCR inductors will reduce
efficiency. To maintain stability, increasing inductor size
will have to be met with an increase in output
capacitance. This is due to the unavoidable “right half
plane zero” effect for the continuous current boost
converter topology. The frequency at which the right half
plane zero occurs can be calculated as follows:
Input capacitor
A minimum 2.2µF ceramic capacitor with an X5R or X7R
dielectric is recommended for designing with the
MIC2299. Increasing input capacitance will improve
performance and provide greater noise immunity on the
source. The input capacitor should be as close as
possible to the inductor and the MIC2299, with short
traces for good noise performance.
The MIC2299 utilizes a feedback pin to compare the
LED current to an internal reference. The LED current is
adjusted by selecting the appropriate feedback resistor
value. The desired output current can be calculated as
follows:
2
f rhpz =
VOUT
VIN
⋅ L ⋅ I OUT ⋅ 2π
The right half plane zero has the undesirable effect of
increasing gain, while decreasing phase. This requires
that the loop gain is rolled off before this has significant
effect on the total loop response. This can be
accomplished by either reducing inductance (increasing
RHPZ frequency) or increasing the output capacitor
value (decreasing loop gain).
I LED =
Compensation
The comp pin is connected to the output of the voltage
error amplifier. The voltage error amplifier is a
transconductance amplifier. Adding a series RC-toground adds a zero at:
Output Capacitor
Output capacitor selection is also a trade-off between
performance, size, and cost. The recommended value
for most applications should be 4.7µF. Increasing output
capacitance will lead to an improved transient response,
but also an increase in size and cost. X5R or X7R
dielectric ceramic capacitors are recommended for
designs with the MIC2299.
The output capacitor sets the frequency of the dominant
pole and zero in the power stage. The zero is given by:
fz =
f zero =
1
2πR 2C 4
The resistor typically ranges from 10kΩ to 50kΩ. The
capacitor typically ranges from 1nF to 100nF. For most
application, the value 33nF and 620Ω are optimum.
Adding an optional capacitor from comp pin-to-ground
adds a pole at:
f pole =
1
C ⋅ R esr ⋅ 2π
1
2πR 2C 3
This capacitor typically ranges from 100pF to 10nF.
Generally, an RC to ground is all that is needed. The RC
should be placed as close as possible to the
compensation pin. The capacitor should be a ceramic
with a X5R, X7R, or COG dielectric.
For ceramic capacitors, the ESR is very small. This puts
the zero at a very high frequency where it can be
ignored.
The frequency of the pole caused by the output
capacitor is given by.
fp =
0.2V
R
I OUT
C ⋅ VOUT ⋅ 2 ⋅ π
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MIC2299
Application Information
This simplifies to I RMS = I PK ⋅ DC when there is no DC
level.
The graph in Figure 9 shows the peak LED current
which can be pulsed at a given duty cycle (DC) to stay
within SOA limits of 400mA to 700mA.
Grounding
Both the AGND and PGND must be connected to the
exposed backside pad. The exposed backside pad also
improves thermal performance. A large ground plane
decreases thermal resistance to ambient air.
Thermal Considerations and the SOA
The SOA (safe operating area) of the MIC2299 is shown
in the typical characteristics section. This graph
represents the maximum continuous output power
capability of the part when used on a minimal evaluation
board layout. This is a 2 layer board of 1 ounce copper,
utilizing the bottom layer as a ground plane heat sink.
The total area of the GND copper is approximately 1.3
square inches. This approaches a thermal resistance of
45oC/W. An alternative layout with more copper area for
heat sinking will increase the area under the SOA curve.
Note that the SOA is for continuous power and not peak
power and is effectively a thermal limitation. The SOA is
true for a time constant of approximately >1 seconds.
Therefore, any load transient with a period of < 3s can
exceed the SOA curve power up to a maximum limited
by the current limit of the MIC2299. Figure 8 shows the
theoretical output current limit of the MIC2299 using the
Evaluation Board inductor value of 2.2µH with a DCR
50mΩ.
Figure 9. Duty Cycle vs. Peak Current
for Fixed RMS Current
Example
Two series connected high brightness white LEDs with a
Vf max of 4.2V and peak current of 800mA require
pulses of 300ms at 3 second intervals. Power source is
a Li-ion cell of 3V min.
Figure 8. Peak Output Current vs. VOUT
If our load is within these limits, it is possible to drive the
load at some repetition rate or duty cycle (DC). This is
allowed as long as we limit the RMS current to below the
SOA limit.
The RMS current for a pulsed current is known to be
I RMS = I PK − PK ⋅ DC + I DC where the current pulse IPK-PK
sits on a DC level of IDC.
(
October 2007
•
Looking at the SOA curves, this cannot be
driven continuously.
•
The time constant of the driver is <3 seconds, so
we can look at the peak current capability of the
driver in Figure 8.
•
Looking at Figure 8, the MIC2299 can achieve
more than the required 800mA peak current at
8.4V
•
Reading from the SOA curve in the typical
characteristics section, the MIC2299 at 3V, 50oC
and 8.4V output voltage, can provide 580mA
RMS.
•
Now looking at the curve in Figure 9, using the
next lower value of 500mA RMS current, we can
see that the 850mA peak can be driven at a duty
cycle of ~33% (or 1 second out of every 3
seconds). That is well within our target of
300ms.
)
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MIC2299
LED Protection
The operation of the Power LED must be limited to short
pulses to prevent overheating. This is usually controlled
by the micro controller in a typical application. For further
fail-safe protection, or where a micro controller is not
used, the temperature of the LED can be limited by the
addition of an NTC thermistor. The value should be
>100kΩ at its maximum safe operating temperature.
This will then limit current drive to the LED as
temperature rises further and prevents overheating. This
thermistor should be connected directly from BRT to
GND. Reference Figure 10.
Figure 10. LED Thermal Protection
October 2007
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M9999-101907-B
Micrel, Inc.
MIC2299
Package Information
12-Pin 3mm x 3mm MLF® (ML)
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its
use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product
can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant
into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A
Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully
indemnify Micrel for any damages resulting from such use or sale.
© 2007 Micrel, Incorporated.
October 2007
14
M9999-101907-B
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