ADSP-BF50x Blackfin Processor Hardware Reference
14-21
PWM Controller
appropriate for safety, emergency dead-time is inserted to prevent
shoot-through conditions.
The insertion of additional emergency dead time into one of the PWM
signals of a given pair during these transitions is necessary only when both
PWM signals are required to toggle within a dead time of each other.
The additional emergency dead time delay is inserted into the PWM sig-
nal that is toggling into the “on” state. In effect, the turn on (if turning on
during this dead time region) of this signal is delayed by an amount
(2*
PWM_DT
*t
SCLK
) from the rising edge of the opposite output. After this
delay, the PWM signal is allowed to turn on, provided the desired output
is still scheduled to be in the on state after the emergency dead time delay.
Figure 14-5
illustrates two examples of such transitions. In the top half
(marked A) of
Figure 14-5
, no special action (dead time) is needed when
transitioning from normal modulation to full on mode at the half cycle
boundary in double-update mode. However, in the bottom half
(marked B) of
Figure 14-5
, when transitioning from normal modulation
into full off mode at the same boundary, it can be seen that an additional
emergency dead time is necessary (inserted by the PWM Controller).
Clearly, this inserted dead time is different from the normal dead time as
it is impossible to move one of the switching events back in time, because
this would take it into the previous modulation cycle. Therefore, the
entire emergency dead time is inserted by delaying the turn on of the
appropriate signal by the full amount.
Содержание EZ-KIT Lite ADSP-BF506F
Страница 50: ...Contents l ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 92: ...Development Tools 1 30 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 110: ...Interface Overview 3 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 132: ...Unique Information for the ADSP BF50x Processor 4 22 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 236: ...Internal Flash Memory Control Registers 6 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 342: ...Unique Information for the ADSP BF50x Processor 7 106 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 484: ...Unique Information for the ADSP BF50x Processor 10 60 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 493: ...ADSP BF50x Blackfin Processor Hardware Reference 11 9 Core Timer Unique Information for the ADSP BF50x Processor None ...
Страница 494: ...Unique Information for the ADSP BF50x Processor 11 10 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 506: ...Unique Information for the ADSP BF50x Processor 12 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 544: ...Unique Information for the ADSP BF50x Processor 13 38 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 650: ...Programming Examples 15 56 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 712: ...Unique Information for the ADSP BF50x Processor 16 62 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 804: ...Programming Examples 17 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 972: ...Unique Information for the ADSP BF50x Processor 20 38 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1194: ...Programming Examples 24 90 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1256: ...ACM Registers A 50 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1264: ...Boundary Scan Architecture B 8 ADSP BF50x Blackfin Processor Hardware Reference ...