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3.4 Controlling Multiple Buck Converters With Same Frequencies
CTR=zero
CTR=CMPB
X
En
Φ=0°
SyncOut
Phase reg
Ext SyncIn
(optional)
EPWM1A
EPWM1B
SyncOut
Phase reg
CTR=CMPB
CTR=zero
X
Φ=X
En
EPWM2B
EPWM2A
Slave
Master
Buck #1
Vout1Vin1
EPWM1A
Buck #2
Vin2
EPWM1B
Vout2
Buck #4
Buck #3
Vin3
EPWM2B
Vin4
EPWM2A
Vout3
Vout4
SyncIn
SyncIn
Controlling Multiple Buck Converters With Same Frequencies
If synchronization is a requirement, ePWM module 2 can be configured as a slave and can operate at
integer multiple (N) frequencies of module 1. The sync signal from master to slave ensures these modules
remain locked. Figure 3-5 shows such a configuration; Figure 3-6 shows the waveforms generated by the
configuration.
Figure 3-5. Control of Four Buck Stages. (Note: F
PWM2
= N x F
PWM1
)
SPRU791D – November 2004 – Revised October 2007 Applications to Power Topologies 75
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