MB3828 Fujitsu Microelectronics, Inc., MB3828 Datasheet - Page 18

• Manufacturer Part Number: MB3828
• Description: Pentium DC/DC Converter ic
• Manufacturer: Fujitsu Microelectronics, Inc.

18
MB3828
DC/DC CONVERTER INPUT VOLTAGE (Vin) AND VB VOLTAGE SETTING
The voltage at the CB pin is bootstrapped from the VS pin voltage by an amount equivalent to the VB pin voltage,
as a result of the bootstrap capacitance (C
or VB pin voltage should be adjusted so that the sum of the DC/DC converter block input voltage Vin plus the
VB pin voltage does not exceed the recommended operating conditions for the CB pin boot voltage (V
CTL LOGIC CIRCUIT OPERATION TIMING CHART
*1: To connect the external low VF diode (Schottky barrier diode) makes VB pin voltage drop reduced
*2: The switching noise can be reduced (0 to 5 ) by connecting the resistance when the external
CTL signal
ENB signal
V
CS pin voltage
DC/DC
output voltage
REF
and then can perform the higher efficiency.
MOSFET gate input capacitance (Ciss) is large, caused by the external MOSFET gate drive
current limiting resistance.
output voltage
Drive
Drive
1
2
13
10
11
12
8
9
VB
CB
OUT1
VS
OUT2
P
GND
ts
B
) between the CB pin and VS pin. Therefore, either the Vin voltage
*
1
C
B
*
*
0.05 V
2
2
DC/DC converter block
toff
V
O
Vin
VB
CB
).