Current mode control type switching power supply device

A current mode control type switching power supply device comprising:

• a first switch having a first terminal connected to a first 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 a second application terminal to which a predetermined voltage lower than the input voltage is applied;
• a current sensor configured to sense current flowing in the second switch;
• and
• a controller configured to control the first switch and the second switch, wherein:
• the controller is configured to control the first switch and the second switch independently of a difference between the input voltage and an output voltage and in addition in accordance with the current sensed by the current sensor, and
• the controller is configured to adjust an on duty of the first switch based on currents sensed by the current sensor at a plurality of times respectively.

An IC comprising:

• a controller configured to control
• a first switch having a first terminal connected to a first 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 a second application terminal to which a predetermined voltage lower than the input voltage is applied;
• and
• a current sensor configured to sense current flowing in the second switch, wherein:
• the controller is configured to control the first switch and the second switch independently of a difference between the input voltage and an output voltage and in addition in accordance with the current sensed by the current sensor, and
• the controller is configured to adjust an on duty of the first switch based on currents sensed by the current sensor at a plurality of times respectively.