bd95710muv-e2 ROHM Co. Ltd., bd95710muv-e2 Datasheet - Page 9

• Manufacturer Part Number: bd95710muv-e2
• Description: 2phase Switching Regulator Controllers Graphic Card
• Manufacturer: ROHM Co. Ltd.

OCP
© 2009 ROHM Co., Ltd. All rights reserved.
BD95710MUV
V
www.rohm.com
IMAX
4.MOSFET Selection
5. OCP Setting Resistance
I
IMAX
IMAX PIN
R
IMAX
VIN_BUS
CSP1
CS1-
CSP2
CSN2
L
r
IL
RL
C
r
Co
VIN_EXT
=
=
L
VOUT
4 x VIN
VIN-VOUT
r
4 x VIN
Pmain=P
(Ron: On-resistance of FET; Ciss: FET gate capacity;
f: switching frequency Crss: FET inverse transfer function;
I
Loss on the synchronous MOSFET
Psyn=P
Loss on the main MOSFET
DRIVE
RL
C
r
: Gate peak current)
RON
x R
RON
9/20
+P
ON
×R
Co
+P
GATE
x I
ON
V
GATE
OUT
I
OUT
OUT
×I
+P
2
OUT
+ Ciss x f x VDD+
TRAN
2
+Ciss×f×VDD
I
IMAX
OCP threshold is determined by external OCP
setting resistance (R
below.
If V
becomes activated.
V
(V
(RL: the DCR value of coil)
IMAX
IMAX
(V
=
IMAX
≦I
CSP1
: OCP Setting Voltage, V
V
IMAX
CSP1
250kΩ
―V
meet the following condition, OCP
×R
―V
CS1
VIN
IMAX
・・・(10)
CS1-
-=I
2
L
x Crss x I
×
＋
IMAX
2 x I
RL
VCSP2―VCSN2
) and I
DRIVE
250kΩ
Technical Note
2009.04 - Rev.B
,
RL=
OUT
IMAX
MAX
x f
=1V)
r×C
calculated
L
・・・(11)
・・・(9)
)