Complementary Outputs And Dead-Time Insertion; Figure 86. Complementary Output With Dead-Time Insertion; Figure 87. Dead-Time Waveforms With Delay Greater Than The Negative Pulse - ST STM32F101 series Reference Manual

Advanced arm-based 32-bit mcus

Hide thumbs Also See for STM32F101 series:

Table of Contents

Advanced-control timers (TIM1&TIM8)

Complementary outputs and dead-time insertion

The advanced-control timers (TIM1&TIM8) can output two complementary signals and

manage the switching-off and the switching-on instants 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

Table 83: Output control bits for complementary OCx and OCxN channels with break

feature on page 350

switching to the 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. DTG[7:0] bits of the TIMx_BDTR register are used to control the

dead-time generation for all channels. 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)

for more details. In particular, the dead-time is activated when

DocID13902 Rev 15