Power module

An operating method of a power module, wherein the power module comprises a gallium nitride transistor, an NMOS transistor electrically connected to the gallium nitride transistor, a first capacitor, a first diode, a second diode, and a power module control terminal, wherein a negative electrode of the first capacitor is electrically connected with an anode of the first diode and the gate of the gallium nitride transistor, and a cathode of the second diode is electrically connected to a gate of the NMOS transistor, and the power module control terminal electrically connected with a positive electrode of the first capacitor and an anode of the second diode, the method comprising the steps of:

• during a first operating period, providing a control signal with a low voltage level to the power module control terminal, so as to turn on the gallium nitride transistor and to let the NMOS transistor is not turned on,
• during a second operating period, transiting the control signal from the low voltage level to a high voltage level, so as to turn on the NMOS transistor and the gallium nitride transistor, wherein the NMOS transistor is kept in a turn-on state subsequently without being affected by the control signal,
• during a third operating period, transiting the control signal from the high voltage level to the low voltage level again, so as to turn off the gallium nitride transistor, wherein the NMOS transistor is turned on continuously;
• and
• during a fourth operating period, transiting the control signal from the low voltage level to the high voltage level again, so as to turn on the gallium nitride transistor, wherein the NMOS transistor is turned on continuously.