The LTC1700 is a current mode synchronous step-up DC/DC controller that drives external N-channel and P-channel power MOSFETs using a constant frequency PWM architecture. Current limiting is provided by sensing the voltage drop across the main MOSFET, eliminating the need of a sense resistor. This No RSENSETM technique helps the LTC1700 maintain high efficiency at heavy loads while Burst Mode operation ensures high efficiency at light loads, thus providing high efficiencies over a wide range of load currents.