MB3886 Fujitsu Microelectronics, Inc., MB3886 Datasheet - Page 22

• Manufacturer Part Number: MB3886
• Description: 2-channel Dc/dc Converter Ic With Overcurrent Protection Symmetrical-phase Type
• Manufacturer: Fujitsu Microelectronics, Inc.

22
MB3886
NOTE ON IC’S INTERNAL POWER CONSUMPTION
The oscillation frequency of an IC and the total gate charge of FETs largely affects the internal dissipation of
the IC.
Pay attention to the following point with respect to the internal power consumption of the IC when applications
are used.
I
applied to the gate capacitors (Ciss
Current per channel
As the current consumption by the IC, excluding I
following equation :
Power consumption : Pc
Pc (W)
B
I
(mean current) is obtained from the following equation, assuming Qg1 and Qg2 as the total gate charges
B
(A)
: = Ibias
I
0.015
1
1
I
2
t1
t
V
CC
(V)
Qg
t
1
2
Ibias
V
CC
1
, Ciss
(V) I
2
2
t2
B
, Crss
t
(A)
1
B
, Crss
, is about 15 mA, the power consumption is obtained from the
Qg
V
t
B
2
(V) I
2
) of external FETs Q1 and Q2.
B
(Ibias
(A)
1
Ibias
2
: = 3 mA)