Adaptive slew rate resonant power converter and conversion control circuit and control method thereof

A conversion control circuit for controlling a resonant power converter, wherein the resonant power converter includes:

• a high-side switch and a low-side switch, coupled to form a half-bridge switching circuit which is configured to switch a transformer for generating an output voltage, wherein the conversion control circuit comprises:
• a high-side drive circuit, generating a high-side drive signal coupled to drive the high-side switch in response to a high-side control signal;
• a switching control circuit, configured to generate a bias voltage, the high-side control signal and a low-side control signal according to the output voltage, wherein the bias voltage is coupled to a bootstrap diode and a bootstrap capacitor for providing a power source from the bootstrap capacitor for the high-side drive circuit, wherein the low-side control signal is configured to control the low-side switch;
• wherein the high-side drive circuit generates the high-side drive signal with a fast slew rate to turn on the high-side switch when the high-side switch is to be turned on with soft-switching, wherein the high-side drive circuit generates the high-side drive signal with a slow slew rate to turn on the high-side switch when the high-side switch is to be turned on without soft-switching.

A control method for controlling a resonant power converter, wherein the resonant power converter includes:

• a high-side switch and a low-side switch, coupled to form a half-bridge switching circuit which is configured to switch a transformer for generating an output voltage;
• and a high-side drive circuit, generating a high-side drive signal coupled to drive the high-side switch in response to a high-side control signal;
• wherein the control method comprises:
• generating a bias voltage, wherein the bias voltage is coupled to a bootstrap diode and a bootstrap capacitor for providing a power source from the bootstrap capacitor for the high-side drive circuit;
• generating the high-side control signal and a low-side control signal according to the output voltage, wherein the low-side control signal is configured to control the low-side switch;
• controlling the high-side drive circuit to generate the high-side drive signal with a fast slew rate to turn on the high-side switch when the high-side switch is to be turned on with soft-switching;
• and
• controlling the high-side drive circuit to generate the high-side drive signal with a slow slew rate to turn on the high-side switch when the high-side switch is to be turned on without soft-switching.