EVALA5973AD STMicroelectronics, EVALA5973AD Datasheet - Page 25

• Manufacturer Part Number: EVALA5973AD
• Description: Power Management Modules & Development Tools EVAL BOARD A5973AD Auto Grade
• Manufacturer: STMicroelectronics
• Type: DC/DC Switching Converters, Regulators & Controllersr

Specifications of EVALA5973AD

• Input Voltage: 4.4 V to 36 V
• Output Voltage: 1.235 V to 35 V
• Board Size: 23 mm x 20 mm
• Product: Power Management Modules
• Supply Current: 2.5 A
• Dimensions: 23 mm x 20 mm
• For Use With/related Products: AN1518
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AN1518
10
10.1
10.2
Application ideas
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 input voltage can range from 5 V and 35 V. The output voltage is given by V
(1-D), where D is the duty cycle. The maximum output current is given by I
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
Buck-boost regulator
In
voltage is given by V
The maximum output current is equal to I
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 equal to V
voltage).
Figure
25, the schematic circuit for a standard buck-boost topology is shown. The output
IN
-V
O
=-V
O
, which must be lower than 36 V (the maximum operating input
IN
· D/(1-D).
OUT
=1 · (1-D), for the same reason as that of the
Application ideas
OUT
=1× (1-D).
O
=V
IN
25/30
· D/