3.4.2.2 Design of Dual SEPIC Supply using uncoupled inductors

This section describes the implementation of the dual HV supply using uncoupled inductors. The specifications of the dual supply is described in Table 1.The sections below provide a step by step method to design the supply. This system can be thought of as two parallel output stages coupled through cap C25 & C35 with the primary side as shown in Figure 11. To create a high voltage dual supply, the output stage of the SEPIC had to be designed differently. As shown in Figure 11, the output capacitors are charged to the positive rail of 80 V for the top stage. Similarly, the output capacitors of the bottom stage are charged to a negative supply of -80 V. This is due to the inclusion of the HVGND shown below between R37 and R44. Using the HVGND. a dual supply SEPIC was achieved. Following the output of both rails, a Pi and Power Filter were used to attenuate the ripple of the high-voltage supply.

Figure 11. SEPIC Converter Schematic