MIC2291 Micrel Semiconductor, MIC2291 Datasheet
MIC2291
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MIC2291 Summary of contents
Page 1
... 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. ...
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... 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 ...
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... 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 ...
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... 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 ...
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... 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- ...
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... 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 ...
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... 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 ...
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... 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 ...
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... 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. ...