An apparatus for driving a power switch tube, comprising:
- a driver;
- a transformer coupled to the driver;
- a power switch tube coupled to the transformer;
- and
- an input circuit coupled to the driver and configured to input a group of drive signals into the driver,
- wherein the group of drive signals comprises a first drive signal, a second drive signal, a third drive signal, and a fourth drive signal,
- wherein the first drive signal and the second drive signal are complementary signals,
- wherein a first dead time is between the first drive signal and the second drive signal for a first field-effect transistor of the first drive signal and a second field-effect transistor of the second drive signal to implement zero-voltage switching,
- wherein the third drive signal and the fourth drive signal are complementary signals,
- wherein a second dead time is between the third drive signal and the fourth drive signal for a third field-effect transistor of the third drive signal and a fourth field-effect transistor of the fourth drive signal to implement zero-voltage switching,
- wherein a first phase difference between the first drive signal and the third drive signal is 180 degree for alternately conducting the first field-effect transistor and the third field-effect transistor,
- wherein a second phase difference between the second drive signal and the fourth drive signal is 180 degree for alternately conducting the second field-effect transistor and the fourth field-effect transistor,
- wherein the driver comprises the first field-effect transistor, the second field-effect transistor, the third field-effect transistor, and the fourth field-effect transistor,
- wherein the driver is configured to power on a field winding of the transformer according to the group of drive signals input by the input circuit,
- wherein the transformer has specified magnetizing inductance and is configured to:
- store energy;
- and
- either input a drive voltage signal into a control end of the power switch tube through the field winding of the transformer according to a stored energy or input a drive voltage signal into the control end of the power switch tube through an induced voltage of an output winding of the transformer induced from the field winding according to the stored energy,
- wherein the power switch tube is coupled to the transformer through the control end and comprises a parasitic capacitor,
- wherein the parasitic capacitor and the transformer constitute a resonant circuit configured to control that the drive voltage signal of the power switch tube has a slow edge rat;
- wherein the transformer is configured such that:
- when the control end of the power switch tube is coupled to an end of the field winding of the transformer, a terminal voltage of the end of the field winding of the power switch tube provides a drive voltage signal for the control end of the power switch tube;
- and
- when the control end of the power switch tube is coupled to the output winding of the transformer, the induced voltage of the output winding of the transformer induced from the field winding provides a drive voltage signal for the control end of the power switch tube.