Abstract: According to one embodiment, a DC-DC converter includes a signal generator configured to output a first PWM signal having arbitrary amplitude and a duty cycle established based on an input voltage and an output voltage, a driver configured to output a second PWM signal being in phase with the first PWM signal and having amplitude of the input voltage based on the first PWM signal, a filter configured to extract a DC component from the second PWM signal, and a switch configured to supply an output of the filter to the signal generator in response to a first control signal.

Abstract: According to one embodiment, a DC-DC converter includes a signal generator configured to output a first PWM signal having arbitrary amplitude and a duty cycle established based on an input voltage and an output voltage, a driver configured to output a second PWM signal being in phase with the first PWM signal and having amplitude of the input voltage based on the first PWM signal, a filter configured to extract a DC component from the second PWM signal, and a switch configured to supply an output of the filter to the signal generator in response to a first control signal.

Abstract: In a mode comparator of the DC-DC converter, a threshold input to the mode comparator is switched to a first threshold, if a mode signal prescribes an active mode, on the other hand, the threshold input to the mode comparator is switched to a second threshold, which is higher than the first threshold, if the mode signal prescribes an inactive mode. A lower limit value to a lower limit value setting circuit of the DC-DC converter is switched to a first lower limit value, if the mode signal prescribes the active mode, on the other hand, the lower limit is switched to a second lower limit value, which is higher than the first lower limit value, if the mode signal prescribes an inactive mode.

Abstract: In a mode comparator of the DC-DC converter, a threshold input to the mode comparator is switched to a first threshold, if a mode signal prescribes an active mode, on the other hand, the threshold input to the mode comparator is switched to a second threshold, which is higher than the first threshold, if the mode signal prescribes an inactive mode. A lower limit value to a lower limit value setting circuit of the DC-DC converter is switched to a first lower limit value, if the mode signal prescribes the active mode, on the other hand, the lower limit is switched to a second lower limit value, which is higher than the first lower limit value, if the mode signal prescribes an inactive mode.

Abstract: A DC-DC converter according to the present invention includes a monitoring circuit which monitors an output signal of a mode comparator and which outputs a mode change detection signal when the output of the mode comparator has output a light load mode signal, and a clamp circuit which is connected between power supply and ground and which changes a voltage at a first end of a filter circuit toward a preset prescribed voltage according to the mode change detection signal.

Abstract: A boost DC/DC converter has a voltage dividing circuit connected between the output terminal and the ground, that outputs a divided voltage obtained by dividing the output voltage; a reference voltage generating circuit that generates a reference voltage based on the input voltage; an error amplifier that outputs a first signal corresponding to the difference between the divided voltage and the reference voltage; a feedforward circuit that detects the input voltage and outputs a second signal corresponding to a current inversely proportional to the input voltage; a multiplier that multiples the first signal by the second signal and outputs a third signal obtained; and a control circuit that outputs, based on the third signal, a control signal for controlling on/off of the switching transistor so that the divided voltage is equal to the reference voltage.

Abstract: According to one embodiment, a switching transistor changes, based on ON/OFF operations, the direction of an electric current flowing to an inductor. A gate driving unit applies a driving voltage to a gate of the switching transistor. A power-supply switching unit switches, based on a result of comparison of the input voltage and the output voltage, the voltage of a power supply that generates the driving voltage.

Abstract: A DC-DC converter according to the present invention includes a monitoring circuit which monitors an output signal of a mode comparator and which outputs a mode change detection signal when the output of the mode comparator has output a light load mode signal, and a clamp circuit which is connected between power supply and ground and which changes a voltage at a first end of a filter circuit toward a preset prescribed voltage according to the mode change detection signal.

Abstract: A boost DC/DC converter has a voltage dividing circuit connected between the output terminal and the ground, that outputs a divided voltage obtained by dividing the output voltage; a reference voltage generating circuit that generates a reference voltage based on the input voltage; an error amplifier that outputs a first signal corresponding to the difference between the divided voltage and the reference voltage; a feedforward circuit that detects the input voltage and outputs a second signal corresponding to a current inversely proportional to the input voltage; a multiplier that multiples the first signal by the second signal and outputs a third signal obtained; and a control circuit that outputs, based on the third signal, a control signal for controlling on/off of the switching transistor so that the divided voltage is equal to the reference voltage.