PT4108:一节锂电池/两节干电池驱动3W或1W LED,零关断电流,效率高达86%,500KH固定工作频率

GENERAL DESCRIPTION

The PT4108 is a compact, high efficient, and low voltage step-up high brightness LED driver   with an Adaptive Current Mode PWM control loop. It comprises of an error amplifier, a ramp generator, a PWM comparator, a switch pass element and driver. It provides stable and high efficient operation over a wide range of load currents. It operates in stable waveforms without external compensation. The low start-up input voltage below 1V makes it suitable for 1~4 battery cells. The 500KHz high switching rate reduces the size of external components. Besides, the 25A low quiescent current together with high efficiency maintains long battery lifetime. The output current set by the external high precision resistor.

FEATURES

¨          Low Quiescent (Switch-off) Supply Current: 25A

¨          Low Start-up Input Voltage: 1.0V

¨          High efficiency: 86%

¨          Fixed switching frequency: 500KHz

APPLICATIONS

¨          Portable Lighting

¨          Flashlights