4.7 Aux Power

A 24V rail, derived from the input voltage using a flyback converter, powers the housekeeping circuitry on the secondary side of the power board. This voltage is galvanically decoupled from the primary side with 4kV reinforced isolation. Downstream 5V and 3.3V rails are generated using switching and linear regulators, respectively.

A 12V rail derived from the bias winding of the flyback transformer is used to power the aux controller and voltage sense circuitry at the primary side.

Table 4-4 shows the electrical performance for each rail.