MIC2287

MIC2287 MIC2287 Micrel, Inc. 1.2MHz PWM White LED Driver with OVP in 2mm × 2mm MLF™ and Thin SOT-23 General Description The MIC2287 is a 1.2MHz pulse width modulated (PWM), boost-switching regulator that is optimized for constantcurrent, white LED driver applications. With a maximum output voltage of 34V and a switch current of over 500mA, the MIC2287 easily drives a string of up to 8 white LEDs in series, ensuring uniform brightness and eliminating several ballast resistors. The MIC2287 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 as opposed 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 MIC2287 is available with 3 levels of overvoltage protection, 15V, 24V, and 34V. This allows designers to choose the smallest possible external components with the appropriate voltage ratings for their applications. The MIC2287 is available in low profile Thin SOT-23 5-lead and an 8-lead 2mm × 2mm MLF™ package options. The MIC2287 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.co...