DC-DC controller and control method thereof

A DC-DC control method, configured to employ an output stage to provide an output voltage after receiving an input voltage, the DC-DC control method comprising:

• generating an adjusting signal according to a variation of the output voltage;
• providing a ramp signal according to the adjusting signal and an output of a ramp oscillator;
• when the adjusting signal has a first logic level, maintaining the ramp signal at a first predetermined level for a predetermined time, wherein the first predetermined level is lower than a level of an error signal related to the output voltage;
• generating a first signal according to the error signal and the ramp signal;
• and
• generating a PWM signal to control the operation of the output stage according to the first signal.

A direct current (DC)-DC controller coupled to an output stage where the output stage receives an input voltage and provides an output voltage, the DC-DC controller comprising:

• a transient boost circuit, generating an adjusting signal having a logic level according to a variation of the output voltage;
• a ramp oscillator;
• a combination logic circuit, coupled to the transient boost circuit and the ramp oscillator, and providing a ramp signal according to the adjusting signal and an output of the ramp oscillator, the combination logic circuit adjusting a level of the ramp signal according to the logic level of the adjusting signal, wherein when the adjusting signal has the first logic level, the combination logic circuit adjusts the ramp signal so that the ramp signal is maintained at a first predetermined level for a predetermined time, wherein the first predetermined level is lower than a level of an error signal related to the output voltage;
• a first comparator, coupled to the combination logic circuit, and generating a first signal according to an error signal and the ramp signal;
• and
• a pulse width modulation (PWM) generator, coupled to the first comparator, and generating a PWM signal to control the operation of the output stage according to the first signal.

A DC-DC control method, configured to employ an output stage to provide an output voltage after receiving an input voltage, the DC-DC control method comprising:

• generating an adjusting signal according to a variation of the output voltage;
• providing a ramp signal according to a logic level of the adjusting signal and an output of a ramp oscillator, wherein when the adjusting signal has the first logic level, the step of providing the ramp signal according to the logic level of the adjusting signal and the output of the ramp oscillator further comprises:
• maintaining the ramp signal at a first predetermined level for a predetermined time, wherein the first predetermined level is lower than a level of an error signal related to the output voltage;
• generating a first signal according to an error signal and the ramp signal;
• and
• generating a PWM signal to control the operation of the output stage according to the first signal.