AP3008,pdf datasheet (WHITE LE

The AP3008 is a 1.2MHz PWM boost switching regulator designed for constant-current white LED driver applications.The AP3008 can drive a string of up to 4 white LEDs from a 3.2V supply or 6 white LEDs from a 5V supply in series, ensuring uniform brightness and eliminating several ballast resistors. The AP3008 implements a constant frequency 1.2MHz PWM control scheme.
The high frequency PWM operation also saves board
space by reducing external component sizes. To
improve efficiency, the feedback voltage is set to 95
mV, which reduces the power dissipation in the current
setting resistor.
The AP3008 is equipped with OVP protection ability,
the SW pin monitors the output voltage and will turn
off the device if an overvoltage condition is present to
prevent damage from an open circuit condition.
The AP3008 is available in SOT-23-5 package.