MB3889 Datasheet, PDF (5/35 Pages) Fujitsu Component Limited. – 2-Channel DC/DC Converter IC with Overcurrent Protection Symmetrical-Phase Type

MB3889
s BLOCK DIAGRAM
FB1 2
−INE1 1
L priority
CS1 3
VREF ^{3 µA}
100
kΩ
Buff
CTL1 9
Open : CH1 ON
L : CH1 OFF
CTL1 = H
VTH = 1.4 V
6 kΩ
Error
− ^Amp1
++
1.23 V
OVP
+ ^Comp.1
−
1.38 V
VCC
24
VB Reg.
L priority
PWM
++ ^Comp.1
−
CH1
Drv
1-1
Max Duty 81%
Dtr ± 6%
Drv
2-1
Current
Protection
Logic
H: at OCP
OCP
Comp.1
118 µA
5.1 V
22 VB
30 CB1
29 OUT1-1
28 VS1
27 OUT2-1
26 PGND1
25 ILIM1
FB2 14
−INE2
CS2
L priority
15
13
VREF ^{3 µA}
Error
Amp2
−
++
1.23 V
OVP
+ ^Comp.2
100
kΩ
Buff
CTL2 10
Open : CH2 ON
L : CH2 OFF
CTL2 = H
VTH = 1.4 V
6 kΩ
−
1.38 V
L priority _PWM
Comp.2
++
−
Max Duty 81%
Dtr ± 6%
CH2
Drv
1-2
Drv
2-2
Current
Protection
Logic
H: at OCP
OCP
Comp.2
118 µA
16 CB2
17 OUT1-2
18 VS2
19 OUT2-2
20 PGND2
23 ILIM2
H: priority
SCP Comp.
H: at OVP
3.1 V
CTL
CTL1
CTL2
Latch1
SQ
R
H: at OVP
H: at OVP
H: at OCP
H: at SCP
10 µA
CSCP 11
CTL
CTL1
CTL2
VREF
SR
Latch
Latch2
UVLO
3.0 V
CT1
1.8 V
3.0 V
CT2
1.8 V
OSC
45 pF
5
RT
H: at
UVLO release
L: at protection
operation
PWRGOOD
12
Protection
control
signal
to Error amp reference
bias
1.23 V _VCC
VREF
Power
VR1 ON/OFF
CTL
3.5 V
8
VREF
7
SGND
4 N.C.
21 N.C.
6 CTL
H : ON (Power On)
L : OFF (Standby mode)
VTH = 1.4 V
5