BD9536FV ROHM Co. Ltd., BD9536FV Datasheet - Page 9

• Manufacturer Part Number: BD9536FV
• Description: 2ch Switching Regulators For Desktop Pc
• Manufacturer: ROHM Co. Ltd.

●Explanation of Operation
H
(Normal operation)
(VOUT drops due to a rapid load change)
●Timing Chart
3
・Soft Start Function
Reg
V
The BD9536FV is a 2ch switching regulator controller incorporating ROHM’s proprietary H
When VOUT drops due to a rapid load change, the system quickly restores VOUT by extending the TON time interval.
REF
REF
OUT
HG
LG
REF
EN
IIN
FB
FB
HG
TM
LG
Io
control
T
SS(ON)
T
ON
+α
9/17
Soft start is utilized when the EN pin is set high. Current
control takes effect at startup, enabling a moderate
“ramping start” on the ouput voltage. Soft start timing
and input current are determined via formula (2) and (3)
below.
Rush current:
(Css: Soft start capacitor; Co: Output capacitor)
When FB falls below the threshold voltage (REF), a drop
is detected, activating the H
HG output is determined by the formula above.
Soft start time:
When FB (V
the voltage remains below REF after the programmed
t
restores V
transient response.
Tss
IIN =
ON
t
ON
(ON
=
time interval has elapsed, the system quickly
)= 50kΩ×Css [sec]
Co×VOUT
REF
VIN
OUT
Tss
OUT)
×
by extending the t
drops due to a rapid load change, and
1
f
[A]
3
[sec]・・・(1)
Reg CONTROLLA control system.
・・・(3)
3
REG CONTROLLA system.
・・・(2)
ON
time, improving