STEVAL-ISV006V1 STMicroelectronics, STEVAL-ISV006V1 Datasheet - Page 5

• Manufacturer Part Number: STEVAL-ISV006V1
• Description: IC LINEAR
• Manufacturer: STMicroelectronics

Specifications of STEVAL-ISV006V1

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 497-11418

AN3319
2
Boost switching application
A step-up (or boost) converter is a switching DC-DC converter able to generate an output
voltage higher than (or at least equal to) the input voltage.
Referring to
square waveform generated by a PWM controller.
When Sw is closed (T
depending on the voltage across the inductor and its inductance value. During this time the
output voltage is sustained by Cout and the diode does not allow any charge transfer from
the output to input stage.
When Sw is open (T
voltage at the input is higher than the output voltage. During this phase the current in the
inductor decreases while the output voltage increases.
Figure 3
Figure 3.
The energy stored in the inductor during T
T
where “D” is the duty cycle of the square waveform driving the switching element.
Boost applications can work in two different modes depending on the minimum inductor
current within the switching period, that is if it is not null or null respectively:
●
●
D
off
, therefore the relation between T
=
Continuous mode (CM)
Discontinuous mode (DCM)
-------------------------------- -
(
Ton
shows the behavior of inductor current.
Ton
+
Toff
Figure
Inductor current in continuous mode
)
1, the switching element (Sw) is typically driven by a fixed frequency
off
on
), the current in the inductor is forced, flowing toward the output until
) the inductor stores energy and its current increases with a slope
Doc ID 18265 Rev 1
on
and T
on
off
is ideally equal to the energy released during
can be written as follows:
Boost switching application
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