MIC2289
Description
The MIC2289 is a PWM (pulse width modulated), boostswitching regulator that is optimized for constant-current white LED driver applications. The MIC2289 features an internal Schottky diode and three levels of output overvoltage protection providing a small size and efficient DC/DC solution that requires only four external ponents. To optimize efficiency, the feedback voltage is set to only 95m V. This reduces power dissipation in the current set resistor and allows the lowest total output voltage, hence minimal current draw from the battery. The MIC2289 implements a constant frequency 1.2MHz PWM control scheme. The high frequency, PWM operation saves board space by reducing external ponent sizes. The added benefit of the constant frequency PWM scheme in caparison to varible frequency is much lower noise and input ripple injected to the input power source. The MIC2289 clamps the output voltage in case of open LED conditions, protecting itself and the output capacitor. The...
