Complementary Outputs And Dead-Time Insertion; Figure 173. Complementary Output With Dead-Time Insertion; Figure 174. Dead-Time Waveforms With Delay Greater Than The Negative Pulse - STMicroelectronics STM32F05 series Reference Manual

RM0091
18.4.11

Complementary outputs and dead-time insertion

The TIM15/16/17 general-purpose timers can output one complementary signal and
manage the switching-off and switching-on of the outputs.
This time is generally known as dead-time and you have to adjust it depending on the
devices you have connected to the outputs and their characteristics (intrinsic delays of level-
shifters, delays due to power switches...)
You can select the polarity of the outputs (main output OCx or complementary OCxN)
independently for each output. This is done by writing to the CCxP and CCxNP bits in the
TIMx_CCER register.
The complementary signals OCx and OCxN are activated by a combination of several
control bits: the CCxE and CCxNE bits in the TIMx_CCER register and the MOE, OISx,
OISxN, OSSI and OSSR bits in the TIMx_BDTR and TIMx_CR2 registers. Refer to
Output control bits for complementary OCx and OCxN channels with break feature on
page 414
IDLE state (MOE falling down to 0).
Dead-time insertion is enabled by setting both CCxE and CCxNE bits, and the MOE bit if the
break circuit is present. There is one 10-bit dead-time generator for each channel. From a
reference waveform OCxREF, it generates 2 outputs OCx and OCxN. If OCx and OCxN are
active high:
●
The OCx output signal is the same as the reference signal except for the rising edge,
which is delayed relative to the reference rising edge.
● The OCxN output signal is the opposite of the reference signal except for the rising
edge, which is delayed relative to the reference falling edge.
If the delay is greater than the width of the active output (OCx or OCxN) then the
corresponding pulse is not generated.
The following figures show the relationships between the output signals of the dead-time
generator and the reference signal OCxREF. (we suppose CCxP=0, CCxNP=0, MOE=1,
CCxE=1 and CCxNE=1 in these examples)

Figure 173. Complementary output with dead-time insertion.

OCxREF

Figure 174. Dead-time waveforms with delay greater than the negative pulse.

OCxREF
for more details. In particular, the dead-time is activated when switching to the
OCx
OCxN
OCx
OCxN
Doc ID 018940 Rev 1
General-purpose timers (TIM15/16/17)
delay
delay
delay
Table 54:
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