The soft-start feature of the DC1909A controls the output voltage slew rate at start-up, reducing current surges and voltage overshoots. Operation Mode Jumpers on the Demonstration Circuit Board allow Burst Mode®, Discontinuous Current Mode, and Continuous Current Mode to be selected. Both Burst Mode operation and Discontinuous Current Mode increase the efficiency at light loads. Continuous Current Mode will maintain a constant switching frequency regardless of the load current.
The average current control loop regulates the maximum output current of the switching regulator. An optional Low Dropout (LDO) circuit is provided on the bottom side of the board for programming the LT3840 current limit set point.