MIC2291-15BML MICREL [Micrel Semiconductor], MIC2291-15BML Datasheet

no-image

MIC2291-15BML

Manufacturer Part Number
MIC2291-15BML
Description
1.2A PWM Boost Regulator Photo Flash LED Driver
Manufacturer
MICREL [Micrel Semiconductor]
Datasheet

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
MIC2291-15BML
Manufacturer:
MICREL/麦瑞
Quantity:
20 000
MLF and
PowerPAK is a trademark of Siliconix, Inc.
General Description
The MIC2291 is a 1.2MHz Pulse Width Modulation (PWM),
boost-switching regulator that is optimized for high-current,
white LED photo flash applications. With a guaranteed switch
current of 1.2A, the MIC2291 easily drives a string of 3 white
LEDs in series at 100mA, ensuring a high level of brightness
and eliminating several ballast resistors.
The MIC2291 implements a constant frequency, 1.2MHz
PWM control scheme. The high frequency PWM operation
saves board space by reducing external component sizes.
The added benefit of the constant frequency PWM scheme,
in contrast to variable frequency topologies, is much lower
noise and input ripple injected back to the battery source.
To optimize efficiency, the feedback voltage is set to only
95mV. This reduces the power dissipation in the current set
resistor, and allows the lowest total output voltage, hence
minimal current draw from the battery.
The MIC2291 is available with 2 levels of over-voltage
protection, 15V, and 34V. This allows designers to choose
the smallest possible external components with the appropri-
ate voltage ratings for their applications.
The MIC2291 is available in low-profile, Thin SOT23 5-lead
and 8-lead 2mm 2mm MLF™ package options. The MIC2291
has a junction temperature range of –40 C to +125 C.
All support documentation can be found on Micrel’s web
site at www.micrel.com.
Typical Application
August, 2004
MIC2291
3V to 4.2V
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
1-Cell
Li Ion
Micro
LeadFrame are trademarks of Amkor Technology, Inc.
Thin SOT23 Flash LED Driver
1 F
5
4
MIC2291BD5
VIN
EN
10 H
GND
2
SW
FB
1
3
95mV
0.95
100mA
0.22 F
ceramic
1
Features
• 2.5V to 10V input voltage
• Output voltage up to 34V
• 1.2A switch current
• 1.2MHz PWM operation
• 95mV feedback voltage
• Overvoltage protection (OVP)
• Stable with ceramic capacitors
• <1% line and load regulation
• 1 A shutdown current
• Over temperature protection
• UVLO
• Low-profile Thin SOT23-5 package option
• 2mm
• –40 C to +125 C junction temperature range
Applications
• Photo Flash LED driver
• Cell phones
• PDAs
• GPS systems
• Digital cameras
• IP phones
• LED flashlights
– Options for 15V and 34V
3V to 4.2V
2mm
1-Cell
Li Ion
2mm MLF™ package option
2mm Flash LED Driver with Output OVP
1.2A PWM Boost Regulator
Photo Flash LED Driver
1 F
MIC2291
MIC2291-15BML
VIN
EN
10 H
GND
OVP
SW
FB
95mV
0.95
100mA
M9999-081104
0.22 F
Micrel

Related parts for MIC2291-15BML

MIC2291-15BML Summary of contents

Page 1

... LED flashlights 100mA 1 1-Cell 0. Ion 3 ceramic 3V to 4.2V 95mV 0.95 2mm 1 MIC2291 1.2A PWM Boost Regulator Photo Flash LED Driver 2mm MLF™ package option 10 H 100mA MIC2291-15BML VIN OVP FB 95mV GND 0.95 2mm Flash LED Driver with Output OVP Micrel 0.22 F M9999-081104 ...

Page 2

... MIC2291 Ordering Information Marking Overvoltage Part Number Code Protection MIC2291BD5 SSAA MIC2291YD5 SSAA MIC2291-15BML STA MIC2291-15YML STA MIC2291-34BML STC MIC2291-34YML STC Pin Configuration FB GND VIN TSOT-23-5 (BD5) Pin Description Pin Number Pin Number TSOT-23-5 2mm 2mm MLF™ Pin Name ...

Page 3

... OUT 10V EN SW TURN ON TURN OFF ( 10V EN MIC2291BML- 15 only MIC2291BML- 34 only Hysteresis , and the ambient temperature The maximum allowable power dissipation will result in excessive (2) ) ........................................ 2.5V to 10V IN ) ........... – +125 C J 2mm MLF™ ......................... 93 C .......................................... 256 C/W ...

Page 4

... MIC2291 Typical Characteristics Efficiency 12V OUT 3. 100 120 140 160 OUTPUT CURRENT (A) Current Limit vs. Temperature 1.4 1.2 1 0.8 0.6 0 -40 - 100 120 TEMPERATURE (°C) Switch Saturation vs. Temperature 700 600 500 400 300 200 100 ...

Page 5

... V REF 95mV * OVP available on MLF Functional Description The MIC2291 is a constant frequency, PWM current mode boost regulator. The block diagram is shown above. The MIC2291 is composed of an oscillator, slope compensation ramp generator, current amplifier, g generator, and a 500mA bipolar output transistor. The oscillator generates a 1.2MHz clock. The clock’s two func- ...

Page 6

... M9999-081104 node voltage to exceed its maximum voltage rating, possibly damaging the IC and the external components. To ensure the highest level of protection, the MIC2291 OVP pin will shut the switch off when an over-voltage condition is detected saving itself and other sensitive circuitry downstream. Component Selection ...

Page 7

... PWM dimming control is implemented by applying a PWM signal on EN pin as shown in Figure 1. The MIC2291 is turned on and off by the PWM signal. With this method, the LEDs operate with either zero or full current. The average LED current is increased proportionally to the duty-cycle of the PWM signal ...

Page 8

... MIC2291 Line Transient TIME (100 s/div) Load Step Response TIME (100 s/div) M9999-081104 Normal Operating Waveforms TIME (100 s/div) Enable Response TIME (100 s/div) 8 Micrel August, 2004 ...

Page 9

... MIC2291 Package Information MICREL, INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA + 1 (408) 944-0800 TEL 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. ...

Related keywords