bd9324efj ROHM Co. Ltd., bd9324efj Datasheet - Page 10

• Manufacturer Part Number: bd9324efj
• Description: Simple Step-down Switching Regulator With Integrated Compensation
• Manufacturer: ROHM Co. Ltd.

(3) Design of Feedback Resistance constant
Soft Start Function
EN Function
Set the feedback resistance as shown below.
COMP
ex)
EN
The example of EN driving circuit.
The equivalent internal circuit.
ERRAMP
VIN
+
-
VIN
＋
2.9V(typ)
R 1
R2
V
70k(typ)
OUT
SS
C
FB
SS
＋
－
Feedback voltage 0.900V
ERR
10/13
prevent high inrush current during start up.
connected to SS pin.
to pull the current from EN terminal and make the
EN voltage low.
current when deciding the SS capacitor value.
The buck converter has an adjustable SoftStart function to
The soft-start time is set by the external capacitor
The soft start time is given by;
The EN terminal controls IC’s shut down.
Leaving EN terminal open, makes IC start up automatically.
To shut down the IC, the external component has
The EN threshold voltage is 0.63V (typ.).
Please confirm the overshoot of the output voltage and inrush
T
SS
=
16200 × C
V
OUT
=
SS
R1+R2
R2
[s]
× 0.900
[V]