EVALA5973AD STMicroelectronics, EVALA5973AD Datasheet - Page 20

• 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

Application information
9.4
20/30
Short-circuit protection
In overcurrent protection mode, when the peak current reaches the current limit, the device
reduces the T
frequency to approximately one third of its nominal value (see
protection). In these conditions, the duty cycle is strongly reduced and, in most applications,
this is enough to limit the current to ILIM. In any event, in case of heavy short-circuit at the
output (V
of external components) the current peak could reach values higher than ILIM. This can be
understood considering the inductor current ripple during the ON and OFF phases:
●
Equation 28
●
Equation 29
where V
inductor.
In short-circuit conditions, V
inductor is very small and it could occur that the current ripple in this phase does not
compensate for the current ripple during T
The maximum current peak can be easily measured through the inductor with V
(short-circuit) and V
condition for an extended period, the external components (mainly the inductor and diode)
must be selected based on this value.
Figure 14. Short-circuit current V
ON phase
OFF phase
D
O
is the voltage drop across the diode and DCR
=0 V) and depending on the application conditions (V
ON
down to its minimum value (approximately 250 nsec) and the switching
CC
=V
INMAX
OUT
∆
∆
I
I
L
L
. In cases where application must sustain the short-circuit
is negligible. So during T
=
=
(
----------------------------------------------------------- -
(
------------------------------------------------------------- -
V
V
IN
D
IN
–
= 25 V
–
V
V
out
ON
out
L
–
.
L
–
DCR
DCR
L
L
•
•
I
I
)
)
=
L
=
OFF
is the series resistance of the
T
T
OFF
ON
, the voltage applied to the
Section 3.4: Current
cc
value and parasitic effect
O
= 0 V
AN1518