AN1518

Application ideas

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10

Application ideas

10.1

Positive buck-boost regulator

The device can be used to implement a step-up/down converter with a positive output

voltage. The figure below shows the schematic circuit of this topology for a 12 V output

voltage.

The current capability is reduced by the term (1-D) and so, for example, with a duty cycle of

0.5, and considering on average current through the switch of 2 A, the maximum output

current deliverable to the load is 1 A. This is due to the fact that the current flowing through

the internal power switch is delivered to the output only during the OFF phase.

Figure 24.

Positive buck-boost regulator

10.2

Buck-boost regulator

In Figure 25, the schematic circuit for a standard buck-boost topology is shown. The output

up/down converter. An important thing to take into account is that the ground pin of the

device is connected to the negative output voltage. Therefore, the device is subjected to a

voltage).