MIC2297-15YML TR Micrel Inc, MIC2297-15YML TR Datasheet

IC,Laser Diode/LED Driver,LLCC,10PIN,PLASTIC

MIC2297-15YML TR

Manufacturer Part Number
MIC2297-15YML TR
Description
IC,Laser Diode/LED Driver,LLCC,10PIN,PLASTIC
Manufacturer
Micrel Inc
Type
Backlight, White LEDr
Datasheet

Specifications of MIC2297-15YML TR

Topology
PWM, Step-Up (Boost)
Number Of Outputs
1
Internal Driver
Yes
Type - Primary
Backlight, Flash/Torch
Type - Secondary
White LED
Frequency
525kHz ~ 6.75kHz
Voltage - Supply
2.5 V ~ 10 V
Mounting Type
Surface Mount
Package / Case
10-MLF®, QFN
Operating Temperature
-40°C ~ 125°C
Current - Output / Channel
20mA
Internal Switch(s)
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Voltage - Output
-
Efficiency
-
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
MIC2297-15YMLTR
MIC2297-15YMLTR
3V to 4.2V
General Description
The MIC2297 is a 600KHz PWM boost-switching regulator
that is optimized for driving 6-10 series white LEDs. With
its internal 40V switch and a guaranteed switch current of
1.2A, the MIC2297 easily drives a string of 10 white LEDs
in series at 20mA, ensuring a high level of brightness and
eliminating several ballast resistors.
The MIC2297 implements constant frequency 600KHz
PWM control. The high frequency PWM operation saves
board space by reducing external component sizes. The
added benefit of the constant frequency PWM operation is
much lower noise and input ripple injected back to the
battery source than with variable frequency topologies.
To optimize efficiency, the feedback voltage is set to
200mV. This reduced voltage reduces the power
dissipation in the current set resistor, and allows the lowest
total output voltage, hence minimal current draw from the
battery.
The MIC2297 is available with output over-voltage
protection that protects the IC and external components in
case of open LED conditions.
The MIC2297 is available in low profile small size 10-pin
2.5mm x 2.5mm MLF
junction temperature range of –40°C to +125°C.
___________________________________________________________________________________________________________
Typical Applications
MLF and MicroLeadFrame is a trademark of Amkor Technology, Inc.
March 2008
1-Cell
Li I on
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
1µF
10 Series LED Driver with Output OVP
1µF
VIN
6.8µH-22µH
EN
AGN D
BRT
REF
®
MIC2297
-42BM L
PGND
package. The MIC2297 has a
SW
COMP
OVP
FB
0.1µF
10
0.47µF
/50V
3V to 4.2V
1-Ce ll
Li I on
Features
• 2.5V to 10V input voltage range
• Output voltage up to 40V
• 1.2A switch current
• 600KHz PWM operation
• Trimmed 200mV feedback voltage
• Output over voltage protection (fixed or adjustable)
• PWM Brightness Control
• DAC Brightness Control
• <1% line regulation
• 1µA shutdown current
• Over temperature protection
• UVLO
• 10-pin 2.5mm x 2.5mm MLF
• –40
Applications
• PDAs
• GPS systems
• Smart phones
• Mini PCs
• Digital cameras
• IP phones
• LED flashlights
408
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
10 Series LED Driver with PWM Brightness Control
1µF
o
C to +125
40V PWM Boost Regulator
PWM
1µF
White LED Driver
o
C junction temperature range
VIN
6.8µH-22µH
EN
AGND
BRT
REF
MIC2297
MIC2297
-42BM L
PGND
SW
COMP
OVP
FB
®
package
0.1µF
M9999-032708
10
0.47µF
/50V

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MIC2297-15YML TR Summary of contents

Page 1

... The MIC2297 is a 600KHz PWM boost-switching regulator that is optimized for driving 6-10 series white LEDs. With its internal 40V switch and a guaranteed switch current of 1.2A, the MIC2297 easily drives a string of 10 white LEDs in series at 20mA, ensuring a high level of brightness and eliminating several ballast resistors. ...

Page 2

... Connect the cathode of the LED chain to this pin. Connect current set resistor from this pin to ground. SW Switch Node (Output): Internal power BIPOLAR collector. GND Ground (Return): Backside pad. 2 Lead Finish Package ® 10-Pin 2.5 x2.5 MLF ® 10-Pin 2.5 x2.5 MLF FB REF BRT AGND MIC2297 Pb-Free Pb-Free M9999-032708 ...

Page 3

... 0V 10V EN IN TURN ON TURN OFF V = 10V BRT BRT BRT V = OPEN BRT MIC2297-42BML (nominal voltage) MIC2297-15BML (nominal voltage) Hysteresis , and the ambient temperature (2) ).......................................... 2.5V to 10V IN )....................................40V OUT )..............-40°C to +125°C J ® MLF -10 (θ ).....................................................65°C/W JA Min Typ 2.5 1.8 2.1 4 0.1 190 ...

Page 4

... INPUT VOLTAGE (V) Efficiency for 10 LEDs @ 20mA vs. Input Voltage 6.8µ INPUT VOLTAGE (V) 4 MIC2297 Frequency vs. Input Voltage 800 700 600 500 400 INPUT VOLTAGE (V) LED Current vs. Input Voltage INPUT VOLTAGE (V) LED Current vs. BRT Voltage ...

Page 5

... 6.8µ LED CURRENT (mA Murata LQH32CN100K11 L1 C1 1µF, 16V VIN EN MIC2297BML REF COMP C3 0.22µF, 10V PWM BRT AGND PGND 5 MIC2297 Efficiency for 9 LEDs vs. LED Current 4. 3. 15µ LED CURRENT (mA) C2 0.47µF, 50V SW OVP C4 0.1µF, 10V FB M9999-032708 = 3.6V ...

Page 6

... Micrel Functional Characteristics Enable Characteristics TIME (2ms/div) Waveform 3. LEDs @ 20mA L = 15µH TIME (1µs/div) Mach 2008 LEDs @ 20mA L = 15µ 0.47µV OUT 0A 6 MIC2297 Waveform 3. LEDs @ 5mA L = 15µH 0A TIME (1µs/div) M9999-032708 ...

Page 7

... Micrel Block Diagram 1.245V BRT REF 600kHz Oscillator Mach 2008 FB COMP OVP 1.245V + + Ramp Generator MIC2297 Block Diagram 7 MIC2297 EN SW PWM Generator GND M9999-032708 ...

Page 8

... Micrel Functional Description The MIC2297 is a constant frequency, PWM current mode boost regulator. The MIC2297 uses peak current mode control. The block diagram is shown above. The MIC2297 is composed of an oscillator, slope compensation ramp generator, current amplifier, gm error amplifier, PWM generator, and a 1.2A bipolar output transistor. The oscillator generates a 600kHz clock. The clock’ ...

Page 9

... 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 MIC2297 to switch at full duty cycle in an attempt to maintain the feedback voltage result, the output voltage will climb out of control. This may ...

Page 10

... The input capacitor should be as close as possible to the inductor and the MIC2297, with short traces for good noise performance. The MIC2297 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 ...

Page 11

... 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 Mach 2008 10-Pin Package MLF indemnify Micrel for any damages resulting from such use or sale. © 2005 Micrel, Incorporated. 11 ® (ML) MIC2297 M9999-032708 ...

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