the pt4110 is a high efficiency step-up dc/dc converter designed for driving multiple strings of up to six series-connected white led from a single cell lithium ion battery. it regulates the output current, ideal for driving light emitting diodes (led) whose light intensity is proportional to the current passing through them. the external ballast resistor sets the led current ranging from 5ma to 20ma, which can be easily adjusted using either a dc voltage or a pulse width modulated (pwm) signal alternatively. its low 300mv feedback voltage reduces power loss and improves efficiency. the pt4110 has multiple features to protect itself from fault conditions including built-in over voltage protection, cycle-by-cycle current limit, over temperature shutdown, input under voltage control and integrated soft-start. the pt4110 is available in sot-89-5 and sop-8 packages. features： 2.7v to 5.5v input voltage range； 35v maximum step-up voltage ； <1µa shutdown mode； 1.2mhz fixed frequency operation； cycle-by-cycle current limit； over voltage protection； under voltage lockout； integrated soft-start：thermal shutdown ： frequency jittering for better emi performance：sot89-5 or sop8 package the pt4110 is a high efficiency step-up dc/dc converter designed for driving multiple strings of up to six series-connected white led from a single cell lithium ion battery. it regulates the output current, ideal for driving light emitting diodes (led) whose light intensity is proportional to the current passing through them. the external ballast resistor sets the led current ranging from 5ma to 20ma, which can be easily adjusted using either a dc voltage or a pulse width modulated (pwm) signal alternatively. its low 300mv feedback voltage reduces power loss and improves efficiency. the pt4110 has multiple features to protect itself from fault conditions including built-in over voltage protection, cycle-by-cycle current limit, over temperature shutdown, input under voltage control and integrated soft-start. the pt4110 is available in sot-89-5 and sop-8 packages. features： 2.7v to 5.5v input voltage range； 35v maximum step-up voltage ； <1µa shutdown mode； 1.2mhz fixed frequency operation； cycle-by-cycle current limit； over voltage protection； under voltage lockout； integrated soft-start：thermal shutdown ： frequency jittering for better emi performance：sot89-5 or sop8 package the pt4110 is a high efficiency step-up dc/dc converter designed for driving multiple strings of up to six series-connected white led from a single cell lithium ion battery. it regulates the output current, ideal for driving light emitting diodes (led) whose light intensity is proportional to the current passing through them. the external ballast resistor sets the led current ranging from 5ma to 20ma, which can be easily adjusted using either a dc voltage or a pulse width modulated (pwm) signal alternatively. its low 300mv feedback voltage reduces power loss and improves efficien