14

LTC3726

3726fb

APPLICATIO S I FOR ATIO

Figure 4. Connections for PolyPhase Operation

NDRV

UVLO

LTC3705/25

(MASTER)

SS/FLT

–

+

RUN/SS

LTC3726

(MASTER)

ITH

3726 F05

+

FB/PHASE

FS/SYNC

•

•

NDRV

SS/FLT

LTC3705/25

(SLAVE)

UVLO

RUN/SS

LTC3726

(SLAVE)

ITH

FB/PHASE

FS/SYNC

•

•

PolyPhase Applications

Figure 4 shows the basic connections for using the

LTC3705/LTC3725 and LTC3726 in PolyPhase applica-

tions. One of the phases is always identified as the “mas-

ter,” while all other phases are “slaves.” For the LTC3705/

voltage for undervoltage, performs the open-loop start-up

slaves. The LTC3705/LTC3725 slaves simply stand by and

wait for PWM signals from their respective pulse trans-

formers. Since the SS/FLT pins of each master and slave

LTC3705/LTC3725s are interconnected, a FAULT

(overcurrent, etc.) on any one of the phases will perform

a shutdown/restart on all phases together. The LTC3705/

LTC3725 is put into slave mode by omitting the resistor on

and voltage-loop regulation by driving all slaves to the

same current as the master using the ITH pins. Faults and

shutdowns are communicated via the interconnection of

the RUN/SS pins. The LTC3726 is put into slave mode by