In electronic circuits, MOS tubes are commonly used power switching components, and their gate drive circuit design has a significant impact on performance. Today we will introduce the following three common MOS tube gate drive circuits.

 1. Direct drive : Direct drive circuit is a relatively simple and direct MOS tube gate drive method (directly driving MOS tube through resistors, diodes and other components). Resistor R1 is used to limit current and suppress parasitic oscillation, and its resistance is usually between 10Ω and 100Ω. Resistor R2 provides a discharge circuit for MOS tube shutdown to ensure its rapid shutdown; Zener diodes D1 and D4 protect the gate and source of MOS tube to prevent overvoltage damage. Diode D3 accelerates MOS tube shutdown and improves circuit switching efficiency.

 2. Complementary transistor drive : When the MOS tube is used in high-power scenarios and the PWM chip output signal driving capability is insufficient, a complementary transistor drive circuit is required. When PWM is high, transistor Q3 turns on to drive the MOS tube to turn on; when PWM is low, transistor Q2 turns on to accelerate the MOS tube to turn off. Resistors R1 and R3 limit the current and suppress parasitic oscillation (resistance 10Ω - 100Ω), R2 provides a shutdown discharge circuit, and diode D1 accelerates the MOS tube to turn off.

 3. Coupling drive (coupling drive using a driving transformer) : In special circuit topologies such as Buck converters or dual-tube forward converters, if the driving signal and the power MOS tube do not share a common ground, or the source of the MOS tube is floating, the coupling drive circuit is an ideal choice. It uses the electromagnetic induction principle of the driving transformer to transmit the driving signal, achieve electrical isolation, avoid ground potential interference, and ensure the normal operation of the MOS tube.

Different MOS gate drive circuits are suitable for different scenarios. Direct drive is simple and low-cost, suitable for low-power and low-performance occasions; complementary transistor drive is suitable for high-power needs; coupled drive is for special situations where there is no common ground or the source is floating. In actual design, it is necessary to comprehensively consider factors such as cost and performance according to specific needs, and reasonably select the drive circuit to ensure stable and efficient operation of the MOS tube.