2 Pre-Regulator Requirement

The need for a pre-regulator circuit for the isolated bias power supply device depends whether or not the circuit works for a wide input voltage range. Considering an input voltage range between 8V–16V, as an example for the 12V LV battery depending on SOC, the device used for bias power supply must function over this whole voltage range. Otherwise, a pre-regulator is needed. Apart from the wide input voltage range capability of bias power devices, other factors like line regulation and load regulation also influence the need for the pre-regulator circuit.

Section 2.1 shows different bias supply architectures including the use of a pre-regulator. In Section 3 onwards, pre-regulators are excluded from the block diagrams for clarity. Since there are multiple topologies and multiple associated devices which can be used in the same architectures, a pre-regulator is not always needed.