ncv890101 ON Semiconductor, ncv890101 Datasheet - Page 12

• Manufacturer Part Number: ncv890101
• Description: Automotive Buck Switching Regulator
• Manufacturer: ON Semiconductor

SYNCHRONIZATION
one another by connecting the SYNCO pin of one to the
SYNCI pin of the other (Figure 29). Any number of
NCV890101 can also be synchronized to an external clock
(Figure 30). If a part does not have its switching frequency
controlled by the SYNCI input, it drives the SYNCO pin low
when it turns on the power switch, and drives it high half a
switching period later. When the switching frequency is
controlled by the SYNCI input, the SYNCO pin is held low.
Synchronization starts within 2 ms of soft−start completion.
immediately turn on the power switch. If another rising edge
CIN2
CIN2
Two NCV890101 can be synchronized out−of−phase to
A rising edge at the SYNCI pin causes an NCV890101 to
EN2
EN2
1
2
3
4
5
1
2
3
4
5
VIN
DRV
SYNCO
GND
EN
VIN
DRV
SYNCO
GND
EN
SYNC SLAVE
NCV890101
NCV890101
SYNCI
COMP
SYNCI
COMP
BST
SW
BST
SW
FB
FB
CDRV2
10
9
8
7
6
CDRV 2
10
9
8
7
6
Figure 30. Both NCV890101s Synchronized to External Clock
DBST2
DBST2
CBST2
Figure 29. NCV890101s Synchronized to Each Other
CBST2
RCOMP2
CCOMP2
DFW2
RCOMP2
CCOMP2
DFW2
RFB22
RFB21
L2
RFB1
RFB2
L2
Master Enabled by Battery
#1 Enabled by Battery
Synchronization
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COUT2
COUT2
VOUT2
VOUT2
12
VIN
VIN
CIN1
CIN1
does not arrive at the SYNCI pin within the Master
Reassertion Time, the NCV890101 controls its own
switching frequency, allowing uninterrupted operation in
the event that the clock (or controlling NCV890101) is
turned off.
NCV890101 to fold back its switching frequency, the main
oscillator switching frequency is still derived from the
frequency received at the SYNCI pin. Under these
conditions, the SYNCO pin is held low.
SYNCI pin if it is unconnected.
If internal conditions or excessive input voltage cause an
An external pulldown resistor is not required at the
Synchronization
1
2
3
4
5
1
2
3
4
5
GND
VIN
DRV
SYNCO
EN
GND
VIN
DRV
SYNCO
EN
SYNC MASTER
NCV890101
CLK
NCV890101
SYNCI
COMP
SYNCI
COMP
BST
SW
BST
FB
SW
FB
CDRV1
CDRV1
10
9
8
7
6
10
9
8
7
6
CBST 1
CBST 1
DBST1
DBST1
DFW1
RCOMP1
CCOMP1
DFW1
RCOMP1
CCOMP1
RFB11
RFB12
RFB1
RFB2
L1
L1
COUT1
VOUT1
COUT1
VOUT1