Current mode control type switching power supply device

An integrated circuit comprising:

• a controller configured to control:
• a first switch having a first terminal connected to an application terminal to which an input voltage is applied, and
• a second switch having a first terminal connected to a second terminal of the first switch and a second terminal connected to an application terminal to which a voltage lower than the input voltage is applied;
• a current sense portion configured to sense a signal based on an on-resistance of the second switch;
• a charging switch configured to be connected to the current sense portion and configured to, when the second switch is on, control charging of a capacitor according to the signal based on the on-resistance of the second switch;
• and
• an accumulating portion including the capacitor configured to connect to the charging switch and configured to accumulate information according to the signal based on the on-resistance of the second switch,
• wherein
• the controller includes an error amplifier configured to amplify a difference between a voltage corresponding to an output voltage of a switching power supply device and a reference voltage, and
• the controller controls off timing of the first switch based on a first voltage and an output voltage of the error amplifier, the first voltage being a voltage reflecting the information accumulated by the accumulating portion.

A switching power supply device comprising:

• a first switch having a first terminal connected to an application terminal to which an input voltage is applied;
• a second switch having a first terminal connected to a second terminal of the first switch and a second terminal connected to an application terminal to which a voltage lower than the input voltage is applied;
• a controller configured to control the first switch and the second switch;
• a current sense portion configured to sense a signal based on an on-resistance of the second switch;
• a charging switch configured to be connected to the current sense portion and configured to, when the second switch is on, control charging of a capacitor according to the signal based on the on-resistance of the second switch;
• and
• an accumulating portion configured to connect to the charging switch and configured to accumulate information according to the signal based on the on-resistance of the second switch,
• wherein
• the controller includes an error amplifier configured to amplify a difference between a voltage corresponding to an output voltage of the switching power supply device and a reference voltage, and
• the controller controls off timing of the first switch based on a first voltage and an output voltage of the error amplifier, the first voltage being based on the current flowing in the second switch when the first switch is off and the second switch is on.