Fujitsu ASSP Product
Power Management
8. Initialization
8. Initialization
(1)
Output Voltage Setting
The output voltage of VO1 can be adjusted by
the external resistor divider.
As illustrated below:
(
R
5
VO
1
=
V
×
ref
(
R5
VO1
=
V
×
ref
(2)
Input Signal Setting
EN1
Set EN1 to VIN to start the buck DC/DC converter (VO1). R1 pull-down EN1 to
GND and disable VO1 if EN1 has no input.
EN2
Set EN2 to VIN to start the LDO converter (VO2). R2 pull-down EN2 to GND
and disable VO2 if EN2 has no input.
Power On Reset (POR)
R3 and R4 are the pull-up resistors for POR (Pin 4). A 1M
to placed at either R3 or R4. When R3 has a 1M
POR will be connected VIN. When R4 has a 1M
POR pin will be connected to VO1.
By default, only R3 require a 1M
MB39C026 Evaluation Board
)
(
+
R
6
300
.
=
0
3
V
×
R
6
)
(
+
R6
499k
=
0.3V
×
R6
)
Ω
Ω
k
+
100
k
.
=
1
Ω
100
k
)
+
100k
=
1.8V
100k
resistor and R4 is open; the
resistor and R3 is open; the
resistor while R4 is open.
R5-1
C2
300k
4.7uF
or
499k
R5-2
0R
FB
6
R6
100k
2
V
resistor is required
7/14
VO1
C3
22pF