CONTROL CIRCUIT OF POWER SUPPLY, POWER SUPPLY DEVICE, ELECTRONIC APPARATUS, AND CONTROL METHOD OF POWER SUPPLY

摘要

PROBLEM TO BE SOLVED: To provide a control circuit of a power supply capable of suppressing sudden change in output voltage.SOLUTION: A DC-DC converter 1 generates an output voltage Vo from an input voltage Vi by controlling on/off of a main side transistor T1 and a synchronous side transistor T2. The DC-DC converter 1 includes a control circuit 20 which includes a load current detection circuit 40 for detecting a load current Io. The control circuit 20 also includes a setting circuit 45 for setting the switching operation of the transistors T1 and T2 depending on the magnitude of the load current Io, when an external control signal of L level for commanding operation stop of the DC-DC converter 1 is inputted. The setting circuit 45 maintains both the transistors T1 and T2 in the off state when the load 2 is "a normal load", and controls the transistor T1 on/off based on the output voltage Vo and maintains the transistor T2 in off state when the load 2 is "a heavy load".