User Manual
27 of 562
V 1.0
2021-08-25
XDPP1100 technical reference manual
Digital power controller
Voltage sense
Figure 16
Same cycle mode
2.3.2.8
V
RECT
delay counters
The V
RECT
processing function includes a set of counters. They measure the delay between:
•
Falling (rising) PWM edge driving the synchronous rectification (SR) FETs
•
Rising (falling) edge of the rectification voltage
The rising (falling) edge of V
RECT
is detected by the vrs_comp comparator at the VRSEN input pin. These timers
obtain an indication of the actual (versus programmed) dead time. It should be noted that:
•
The counters operate on a 5 ns clock period.
•
The vrs_comp comparator is clocked on a 5 ns clock period leading to an overall counter accuracy result of
±10 ns.
In addition to the delay counters, a third counter measures the rectification voltage pulse width as detected by
the vrs_comp comparator on the VRSEN input pin. This measurement result is used by the flux (volt-second)
balance function. See
Two versions of the delay count results are available for each edge of the rectification voltage:
•
Block averaged result
•
Non-averaged result
Only the non-averaged result is available for the pulse width measurement, though it is separated into even
and odd measurements for bridge topologies.
shows the timing of the measured waveforms.
PWM
VRSEN
vrect output
same cycle
disabled
Tracking
Window
V
IN
Same Cycle
Window
vrect output
same cycle
enabled