Voltage slew rate limiters for transformer-based switching power converters

A power converter comprising:

• a transformer having a primary winding and a secondary winding;
• a switching stage comprising at least one switching device configured to selectively couple an input voltage of the power converter to the primary winding of the transformer;
• a rectifier stage comprising at least one rectifier device configured to couple the secondary winding of the transformer to an output of the power converter;
• and
• a slew rate limiting circuit further comprising:
• a capacitor coupled between the first terminal and the drive terminal;
• and
• a first diode coupled between the drive terminal and the capacitor, with an anode coupled to the drive terminal of the switching device and a cathode coupled to the capacitor;
• wherein the capacitor and the diode selectively limit a voltage slew rate across the first and second terminals of the switching device by changing a time constant of a gate drive circuit of the at least one switching device to increase a turn-on transition time of the at least one switching device.

A slew rate limiting circuit for a transformer-based switching power converter, the switching power converter having a first switching device with a first terminal, a second terminal, and a drive terminal, the slew rate limiting circuit comprising:

• a capacitor configured to be coupled between the first terminal and the drive terminal of the switching device;
• a second switching device coupled between the drive terminal and the capacitor, with:
• a first terminal of the second switching device coupled to a gate driver of the switching power converter,
• a second terminal of the second switching device coupled to the drive terminal of the first switching device, and
• a drive terminal of the second switching device coupled to the capacitor;
• a resistor coupled between the first and second terminals of the second switching device;
• wherein the resistor, capacitor, and the second switching device selectively limit a voltage slew rate across the first and second terminals of the switching device by changing a time constant of a gate drive circuit of the first switching device to increase a turn-on transition time of the first switching device.

A power converter comprising:

• a transformer having a primary winding and a secondary winding;
• a switching stage comprising at least one switching device configured to selectively couple an input voltage of the power converter to the primary winding of the transformer;
• a rectifier stage comprising at least one rectifier device configured to couple the secondary winding of the transformer to an output of the power converter;
• and
• a slew rate limiting circuit further comprising:
• a capacitor configured to be coupled between the first terminal and the drive terminal of the switching device;
• a second switching device coupled between the drive terminal and the capacitor, with:
• a first terminal of the second switching device coupled to a gate driver of the switching power converter,
• a second terminal of the second switching device coupled to the drive terminal of the first switching device, and
• a drive terminal of the second switching device coupled to the capacitor;
• a resistor coupled between the first and second terminals of the second switching device;
• wherein the resistor, capacitor, and the second switching device selectively limit a voltage slew rate across the first and second terminals of the switching device by changing a time constant of a gate drive circuit of the first switching device to increase a turn-on transition time of the first switching device.