Switched Capacitor Driving Circuits for Power Semiconductors

A driver circuit for driving a power switch, comprising:

• a first switch device coupled in series to a second switch device at an output node of the driver circuit, the first switch device configured to couple the output node to a high-voltage node during an on phase of a switching cycle, the second switch device configured to couple the output node to a low-voltage node during an off phase of the switching cycle;
• a first switched capacitor charge pump configured to apply a negative voltage to the low-voltage node during at least part of the off phase of the switching cycle;
• and
• a biasing circuit,
• wherein the first switched capacitor charge pump comprises:
• a first diode having an anode electrically connected to a source of the second switch device and a cathode electrically connected to a reference voltage rail;
• a first capacitor having a first terminal electrically connected between the anode of the first diode and the source of the second switch;
• and
• a first charging/discharging circuit electrically connected to a second terminal of the first capacitor, the first charging/discharging circuit configured to couple the second terminal of the first capacitor to a positive voltage rail while the second switch device is in an off state and the first switch device is in an on state, and to couple the second terminal of the first capacitor to the reference voltage rail during at least part of the off-phase of the switching cycle,
• wherein the biasing circuit comprises:
• an additional capacitor electrically connected between the high-voltage node and the low-voltage node;
• and
• an additional diode having an anode electrically coupled to the low-voltage node and a cathode electrically coupled to the anode of the first diode.

A driver circuit for driving a power switch, comprising:

• a first switch device coupled in series to a second switch device at an output node of the driver circuit, the first switch device configured to couple the output node to a high-voltage node during an on phase of a switching cycle, the second switch device configured to couple the output node to a low-voltage node during an off phase of the switching cycle;
• and
• a first switched capacitor charge pump configured to apply a negative voltage to the low-voltage node during at least part of the off phase of the switching cycle,
• wherein the output node of the driver circuit is electrically connected to a low-side power transistor,
• wherein a positive voltage rail of the driver circuit is electrically connected to a bootstrap capacitor of a bootstrap circuit for a high-side power transistor through a diode and a resistor,
• wherein the low-side power transistor and the high-side power transistor are coupled in a half bridge configuration.

A driver circuit for driving a power switch, comprising:

• a first switch device coupled in series to a second switch device at an output node of the driver circuit, the first switch device configured to couple the output node to a high-voltage node during an on phase of a switching cycle, the second switch device configured to couple the output node to a low-voltage node during an off phase of the switching cycle;
• and
• a first switched capacitor charge pump configured to apply a negative voltage to the low-voltage node during at least part of the off phase of the switching cycle,
• wherein a capacitance of the first switched capacitor charge pump completely discharges during part of the off phase of the switching cycle.