DC converter

A DC converter having a transformer, a main switch connected in series with a primary winding of the transformer, and a series circuit connected to ends of one of the primary winding and main switch and including a clamp capacitor and an auxiliary switch, the main and auxiliary switches being alternately turned on/off so that a secondary winding of the transformer generates a voltage that is rectified and smoothed with a rectifying/smoothing circuit to provide a DC output, the DC converter comprising:

• a first time difference detector configured to detect a time difference between a point around which the main switch provides a minimum level after the auxiliary switch turns off and a point at which the main switch turns on;
• a second time difference detector having a lower minimum level of detecting sensitivity than the first time difference detector, configured to detect a time difference between a point around which the main switch provides a minimum level after the auxiliary switch turns off and a point at which the main switch turns on;
• an integrator configured to integrate the output of the first time difference detector;
• and
• a delay controller configured to control a turn-on point of the main switch according to the outputs of the integrator and second time difference detector,
• the delay controller operating to minimize the output of the first time difference detector according to the output of the integrator and controlling a turn-on point of the main switch in a pulse-by-pulse manner according to a pulse-by-pulse control signal based on the output of the second time difference detector.

A DC converter having a transformer, a main switch connected in series with a primary winding of the transformer, and a series circuit connected to ends of one of the primary winding and main switch and including a clamp capacitor and an auxiliary switch, the main and auxiliary switches being alternately turned on/off so that a secondary winding of the transformer generates a voltage that is rectified and smoothed with a rectifying/smoothing circuit to provide a DC output, the DC converter comprising:

• a time difference detector configured to detect a time difference between a point around which the main switch provides a minimum level after the auxiliary switch turns off and a point at which the main switch turns on;
• an integrator configured to integrate the output of the time difference detector;
• a first voltage change detector configured to detect a temporal change in the voltage of the main switch;
• and
• a delay controller configured to control a turn-on point of the main switch according to the outputs of the integrator and first voltage change detector,
• the delay controller operating to minimize the output of the time difference detector according to the output of the integrator and controlling a turn-on point of the main switch in a pulse-by-pulse manner according to a pulse-by-pulse control signal based on the output of the first voltage change detector.

A DC converter having a transformer, a main switch connected in series with a primary winding of the transformer, and a series circuit connected to ends of one of the primary winding and main switch and including a clamp capacitor and an auxiliary switch, the main and auxiliary switches being alternately turned on/off so that a secondary winding of the transformer generates a voltage that is rectified and smoothed with a rectifying/smoothing circuit to provide a DC output, the DC converter comprising:

• a time difference detector configured to detect a time difference between a point around which the main switch provides a minimum level after the auxiliary switch turns off and a point at which the main switch turns on;
• an integrator configured to integrate the output of the time difference detector;
• a voltage detector configured to detect a voltage of the main switch;
• and
• a delay controller configured to control a turn-on point of the main switch according to the outputs of the integrator and voltage detector,
• the delay controller operating to minimize the output of the time difference detector according to the output of the integrator and controlling a turn-on point of the main switch in a pulse-by-pulse manner according to a pulse-by-pulse control signal based on the output of the voltage detector.