SS6578

· Notebook 5V/3.3V Main Power
· Step-Down DC/DC Controller Modules.
· Constant-Current Source for Battery Chargers.

The SS6578 is a high performance step-down DC/DC controller, designed to drive an external P-channel MOSFET to generate programmable output voltages. Two main schemes of Pulse-Skipping and Pulse-Frequency Modulation are employed to maintain low quiescent current and high conversion efficiency under wide ranges of input voltage and loading condition. The SS6578 delivers 10mA to 2A of output current with 87%~93% efficiency at V_IN=9V, V_OUT=5V condition. A current-sense comparator with both inverting and non-inverting inputs uncommitted is included to provide the crucial function of either current-limit protection or constant-output current control. When the SS6578 is used in a high-side current-sensing step-down constant-current source, the efficiency is typically greater than 90%. Duty-cycle can be adjusted to greater than 90% by connecting a resistor from DUTY pin to V_IN. Quiescent current is about 90mA and can be reduced to 8mA in shutdown mode. The switching frequency range of around 90 kHz to 280 kHz allows small size switching components, SS6578 is ideal for battery powered portable equipment.