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Smart Sync

V

O

V

I

INH/UVLO

-Sense

GND

GND

Track SYNC TT

VoAdj

C 2

330

F

I

m

C 2

200

F

O

m

R

2

SET

V =5V

I

V 1

O

V 2

O

PTH08T260W

V

CC

GND

f

=2xf

clock

modules

CLK

CLR

SN74LVC2G74

0

o

PRE

D

Q

Q

180

o

+Sense

GND

C 1

200

F

O

m

R

1

SET

C 1

330

F

I

m

V

O

V

I

INH/UVLO

-Sense

GND

Track SYNC TT

VoAdj

PTH08T230W

+Sense

PTH08T260W, PTH08T261W

SLTS272A – DECEMBER 2006 – REVISED MAY 2007

Smart Sync is a feature that allows multiple power modules to be synchronized to a common frequency. Driving

the Smart Sync pins with an external oscillator set to the desired frequency, synchronizes all connected modules

to the selected frequency. The synchronization frequency can be higher or lower than the nominal switching

frequency of the modules within the range of 240 kHz to 400 kHz (see Electrical Specifications table for

frequency limits). Synchronizing modules powered from the same bus, eliminates beat frequencies reflected

back to the input supply, and also reduces EMI filtering requirements. These are the benefits of Smart Sync.

Power modules can also be synchronized out of phase to minimize source current loading and minimize input

capacitance requirements. Figure 22 shows a standard circuit with two modules syncronized 180

° out of phase

using a D flip-flop.

Figure 22. Typical SmartSync Circuit

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