PRD1175, -9V, 9V DC to DC Multi-Output Power Supply

PRD1175, Application Design is a so called cascaded coupled SEPIC-Cuk converter producing clean 9V rails from a 12V input. A SEPIC-Cuk is simply a SEPIC and a Cuk converter designed to share the regulator and power switch. Using coupled inductors for each converter increases the efficiency and improves the frequency response. The cascade in the name refers to Q1 which is a FET in series with the internal FET of the ADP1613. This enables us to use this 20V max rated chip at a higher switch node voltage