20.3.3 Dead-Time Insertion Unit
Some of the timers include a Dead-Time Insertion module suitable for motor control applications. Refer to the device data sheet to
check if a timer has this feature. The example settings in this section are for TIMER0, but identical settings can be used for other timers
with DTI as well. The Dead-Time Insertion Unit aims to make control of brushless DC (BLDC) motors safer and more efficient by intro-
ducing complementary PWM outputs with dead-time insertion and fault handling, see
Figure 20.39 TIMER/WTIMER Dead-Time Inser-
tion Unit Overview on page 669
.
Dead time
insertion
Original PWM (TIM0_CCx_pre)
Fault
handling
Primary output (TIM0_CCx)
Complementary output (TIM0_CDTIx)
Fault sources
Figure 20.39. TIMER/WTIMER Dead-Time Insertion Unit Overview
When used for motor control, the PWM outputs TIM0_CC0, TIM0_CC1 and TIM0_CC2 are often connected to the high-side transistors
of a triple half-bridge setup (UH, VH and WH), and the complementary outputs connected to the respective low-side transistors (UL, VL,
WL shown in
Figure 20.40 TIMER/WTIMER Triple Half-Bridge on page 669
). Transistors used in such a bridge often do not open/
close instantaneously, and using the exact complementary inputs for the high and low side of a half-bridge may result in situations
where both gates are open. This can give unnecessary current-draw and short circuit the power supply. The DTI unit provides dead-
time insertion to deal with this problem.
UH
VH
WH
WL
VL
UL
W
V
U
Figure 20.40. TIMER/WTIMER Triple Half-Bridge
For each of the 3 compare-match outputs of TIMER0, an additional complementary output is provided by the DTI unit. These outputs,
named TIM0_CDTI0, TIM0_CDTI1 and TIM0_CDTI2 are provided to make control of e.g. 3-channel BLDC or permanent magnet AC
(PMAC) motors possible using only a single timer, see
Figure 20.41 TIMER/WTIMER Overview of Dead-Time Insertion Block for a Sin-
Reference Manual
TIMER/WTIMER - Timer/Counter
silabs.com
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