Switch control device, switch control method, and converter using the same

A switch control device of a converter that converts an input signal into an output signal according to a switching operation of a switch, the switch control device comprising:

• a first signal generator configured to generate a first signal, which is maintained at a first level during a first interval after starting from a first time at which the switch is turned on and is then gradually lowered from the first level to a second level;
• a second signal generator configured to selectively output the higher of a third level signal lower than the first level but higher than the second level and the first signal;
• and
• a pulse width modulation (PWM) controller configured to control the switching operation of the switch according to a result obtained by comparing a third signal corresponding to a current flowing at the switch and the output signal of the second signal generator.

A switch control method of a converter that converts an input signal into an output signal according to a switching operation of a switch, the method comprising:

• generating a first signal, which is maintained at a first level during a first interval starting from a first time at which the switch is turned on and is then gradually lowered from the first level to a second level during a second interval;
• and
• generating a second signal by selecting a signal with a higher level among the first signal and a feedback signal corresponding to the output signal;
• comparing a third signal corresponding to a current flowing through the switch and the second signal;
• and
• controlling the switching operation of the switch according to the comparison result.

A switch control method of a converter that converts an input signal into an output signal according to a switching operation of a switch, the method comprising:

• generating a first signal, which is maintained at a first level during a first interval starting from a first time at which the switch is turned on and is then gradually lowered from the first level to a second level during a second interval, and a second signal by selecting a signal with a higher level among the first signal and a third signal lower than the first level but higher than the second level;
• comparing a third signal corresponding to a current flowing through the switch and the second signal;
• and
• controlling the switching operation of the switch according to the comparison result.

A converter comprising:

• a switch;
• an energy transfer element that converts input energy into output energy according to a switching operation of the switch;
• and
• a switch control device configured to generate a first signal, which is maintained at a first level during a first interval starting from a first time at which the switch is turned on by using a feedback signal corresponding to the output energy and is then gradually lowered from the first level to the feedback signal during a second interval, and to control the switching operation of the switch by using a second signal corresponding to a current flowing through the switch and the first signal.

A converter comprising:

• a switch;
• an energy transfer element that converts input energy into output energy according to a switching operation of the switch;
• and
• a switch control device that generates a first signal, which is maintained at a first level during a first interval starting from a first time at which the switch is turned on and is then gradually lowered from the first level to a second level during a second interval, and controls the switching operation of the switch by using a second signal corresponding to a current flowing at the switch and the first signal.