Dc-dc converting circuit and method for controlling the same

A dc-dc converting circuit, comprising:

• an output stage, providing an output voltage;
• a mode detection circuit, coupled to the output stage, and providing a mode detection signal;
• a PWM signal generating circuit, coupled to the output stage, and providing a time signal to the output stage;
• and
• a ramp signal generating circuit, coupled to the PWM signal generating circuit and the mode detection circuit, and providing a first ramp signal or a second ramp signal to the PWM signal generating circuit,
• wherein when the dc-dc converting circuit enters a continuous conduction mode from a discontinuous conduction mode, the ramp signal generating circuit provides the second ramp signal to the PWM signal generating circuit in a preset time according to the mode detection signal, and the ramp signal generating circuit provides the first ramp signal to the PWM signal generating circuit after the preset time,
• wherein a slope of the second ramp signal is greater than a slope of the first ramp signal.