24.3.2.2 Dead-Time Insertion

The Dead-Time Insertion (DTI) unit generates OFF time where the non-inverted low side (LS) and inverted high side (HS) of the Waveform Output (WO) are both low. This OFF time is called dead time, and the Dead-Time Insertion unit ensures that the LS and HS never switch simultaneously.

The DTI unit consists of up to four equal dead-time generators. Figure 24-4 shows the block diagram of one DTI generator. All channels have a mutual register that controls the dead time. The high and low sides have independent dead-time settings, and the dead-time registers are double-buffered.

In Pattern Generation mode, the Dead-Time buffers are not available. Dead-Time can still be implemented using only the data registers, which is the case when PGM is enabled only on some outputs, and Complementary PWM with dead-time is needed on other outputs.

Figure 24-5 shows the 8-bit dead-time counter is decremented by one for each peripheral clock cycle until it reaches zero. A nonzero counter value will force the low and high side outputs into their OFF state.

When detecting a change on the Waveform Output (WOn), the dead-time counter reloads according to the edge of the input. A positive edge initiates a counter reload of the DTLS register. A negative edge initiates a reload of the DTHS register.