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CTR=0
CTR=CMPB
X
En
SyncOut
Phase reg
Ext SyncIn
(optional)
EPWM1A
EPWM1B
SyncOut
Phase reg
CTR=CMPB
CTR=0
X
En
EPWM2B
EPWM2A
Master2
Master1
SyncIn
CTR=0
CTR=CMPB
SyncOut
X
EPWM3B
Phase reg
Master3
En
EPWM3A
1
2
3
Φ=X
Φ=X
Φ=X
CTR=0
CTR=CMPB
SyncOut
X
EPWM4B
Phase reg
Master4
En
EPWM4A
3
Φ=X
Buck #1
Vout1
Vin1
EPWM1A
Buck #2
Vin2
EPWM2A
Vout2
Buck #4
Buck #3
Vin3
EPWM4A
Vin4
EPWM3A
Vout3
Vout4
SyncIn
SyncIn
SyncIn
Applications to Power Topologies
528
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Enhanced High-Resolution Pulse-Width Modulator (eHRPWM)
16.3.3 Controlling Multiple Buck Converters With Independent Frequencies
One of the simplest power converter topologies is the buck. A single ePWM module configured as a
master can control two buck stages with the same PWM frequency. If independent frequency control is
required for each buck converter, then one ePWM module must be allocated for each converter stage.
shows four buck stages, each running at independent frequencies. In this case, all four
ePWM modules are configured as Masters and no synchronization is used.
shows the
waveforms generated by the setup shown in
; note that only three waveforms are shown,
although there are four stages.
Figure 16-51. Control of Four Buck Stages. (Note: F
PWM1
≠
F
PWM2
≠
F
PWM3
≠
F
PWM4
)
NOTE:
Θ
= X indicates value in phase register is a "don't care"