White LED Regulator Steps Up to the Low Noise Challenge

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The MIC3287 from Micrel is a high-performance and space-saving white LED driver.

Offering a maximum output voltage of 24V and a switch current of over 350mA, the MIC3287 step-up switching regulator can drive a string of up to four white LEDs in series. It supports a uniform brightness level and eliminates several ballast resistors.

A current mode control scheme is employed, operating at a constant frequency of 1.2MHz. The high frequency allows smaller external components to be used, minimizing the demand on PCB area. Constant frequency control is employed rather than variable frequency control. Its advantages include much lower noise, with the input ripple current being injected back into the battery source.

To optimize efficiency, the feedback voltage is set to only 250mV. The MIC3287 is also available with a maximum 24V over voltage protection.

 

 

Features <1% line and load regulation <1µA shutdown current Over temperature protection Under voltage lockout Package options: SOT-23-5, SOT-23-6 and 8-pin, 2mm x 2mm MLF -40°C to 125°C temperature range 2.8V to 5.5V input voltage 350mA switch current 1.2MHz PWM operation 250mV feedback voltage 24V output over voltage protection (OVP) option

Applications White LED driver for backlighting: Cell phones PDAs GPS systems Digital cameras MP3 players IP phones LED flashlights Constant current power supplies

 

 

 Featured Products

Part Number		Description	Data Sheet	App. Notes
MIC3287-24YML TR		1.2MHz PWM White LED Driver

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