Dead-Time
It is the short deliberate wait placed between one switch turning on and the other turning off in an H-bridge leg. For silicon MOSFETs it is typically chosen in the 100–300 ns range and prevents the two switches from conducting at the same time.
Dead-time is the timing measure taken against a direct leg short circuit. A MOSFET turning off takes as long as the discharge time of its gate capacitance; if the signals are given perfectly complementary, this delay creates an overlap window. The wait inserted between them allows the switch that is turning off to cut off completely.
Choosing the duration is a balance. Too short a dead-time does not fully close the overlap risk. Too long a dead-time brings two problems: during that period the current circulates through the body diode and produces heat by dropping a typical 0,7–1,2 V across it; besides, the real duty ratio deviates from the desired value, which spoils linearity especially at very low and very high speeds.
In a 20 kHz PWM the period is 50 µs; a 200 ns dead-time is only four thousandths of that and goes unnoticed in practice. The same dead-time corresponds to four percent of the period at 200 kHz and its effect becomes measurable. That is why dead-time and switching frequency are chosen together.
Context where this term is used: DC Motor Driver Selection Guide