Patent ID: 7071667

Claim:
A DC—DC converter comprising the following: a switching power supply unit, which has a switching element that can be turned on/off at high frequency and can turn on/off the aforementioned switching element to convert a DC input voltage into a DC output voltage; an error amplifier, which compares the aforementioned DC output voltage obtained from the aforementioned switching power supply unit with a reference value and outputs an error signal corresponding to the comparison error under a selected response characteristic, that is, either a first response characteristic or a second response characteristic having greater responsivity than the first response characteristic; a switching control unit, which generates a switching drive pulse corresponding to the aforementioned error signal output from the error amplifier for making the DC output voltage consistent with the aforementioned reference value and sends the switching drive pulse to the aforementioned switching element; and a response characteristic selection circuit, which compares the aforementioned DC output voltage with a desired monitoring value and selects the aforementioned first response characteristics as the response characteristic of the aforementioned error amplifier when the DC output voltage is within the range of the aforementioned monitoring value and selects the second response characteristic as the response characteristic of the error amplifier when the DC output voltage is out of the range of the monitoring value.